ar71xx: fix board detection with newer RouterBOOT versions

Recent RouterBOOT version (at least version 3.41 on RB911G-5HPacD)
use "Board=" kernel parameter instead of "board=" to pass the board
name to the kernel. Due to this change the board detection code is
not working on the devices shipped with the new RouterBOOT version.
Because the kernel is unable to identify these boards they become
unusable despite that they are supported by the current code.

Update the prom_init code to convert the 'Board' kernel parameter to
'board'. After this change, the board detection works also with the
new RouterBOOT versions.

Signed-off-by: Gabor Juhos <juhosg@freemail.hu>

target/linux/ar71xx/patches-4.4/702-MIPS-ath79-fixup-routerboot-board-parameter.patch

@@ -0,0 +1,43 @@
+From: Gabor Juhos <juhosg@freemail.hu>
+Date: Sat, 2 Dec 2017 19:15:29 +0100
+Subject: [PATCH] MIPS: ath79: fix board detection with newer RouterBOOT versions
+
+Recent RouterBOOT version (at least version 3.41 on RB911G-5HPacD)
+use "Board=" kernel parameter instead of "board=" to pass the board
+name to the kernel. Due to this change the board detection code is
+not working on the devices shipped with the new RouterBOOT version.
+Because the kernel is unable to identify these boards they become
+unusable despite that they are supported by the current code.
+
+Update the prom_init code to convert the 'Board' kernel parameter to
+'board'. After this change, the board detection works also with the
+new RouterBOOT versions.
+
+Signed-off-by: Gabor Juhos <juhosg@freemail.hu>
+---
+--- a/arch/mips/ath79/prom.c
++++ b/arch/mips/ath79/prom.c
+@@ -104,6 +104,7 @@ static int __init ath79_prom_init_myload
+ void __init prom_init(void)
+ {
+ 	const char *env;
++	char *c;
+ 
+ 	if (ath79_prom_init_myloader())
+ 		return;
+@@ -137,6 +138,15 @@ void __init prom_init(void)
+ 	}
+ #endif
+ 
++	/*
++	 * RouterBOOT uses "Board" kernel parameter instead of "board" since
++	 * version 3.41 (or so). Replace the first character of the parameter
++	 * to keep board detection working.
++	 */
++	c = strstr(arcs_cmdline, "Board=");
++	if (c)
++		c[0] = 'b';
++
+ 	if (strstr(arcs_cmdline, "board=750Gr3") ||
+ 	    strstr(arcs_cmdline, "board=750i") ||
+ 	    strstr(arcs_cmdline, "board=750-hb") ||

target/linux/ar71xx/patches-4.9/702-MIPS-ath79-fixup-routerboot-board-parameter.patch

@@ -0,0 +1,43 @@
+From: Gabor Juhos <juhosg@freemail.hu>
+Date: Sat, 2 Dec 2017 19:15:29 +0100
+Subject: [PATCH] MIPS: ath79: fix board detection with newer RouterBOOT versions
+
+Recent RouterBOOT version (at least version 3.41 on RB911G-5HPacD)
+use "Board=" kernel parameter instead of "board=" to pass the board
+name to the kernel. Due to this change the board detection code is
+not working on the devices shipped with the new RouterBOOT version.
+Because the kernel is unable to identify these boards they become
+unusable despite that they are supported by the current code.
+
+Update the prom_init code to convert the 'Board' kernel parameter to
+'board'. After this change, the board detection works also with the
+new RouterBOOT versions.
+
+Signed-off-by: Gabor Juhos <juhosg@freemail.hu>
+---
+--- a/arch/mips/ath79/prom.c
++++ b/arch/mips/ath79/prom.c
+@@ -104,6 +104,7 @@ static int __init ath79_prom_init_myload
+ void __init prom_init(void)
+ {
+ 	const char *env;
++	char *c;
+ 
+ 	if (ath79_prom_init_myloader())
+ 		return;
+@@ -137,6 +138,15 @@ void __init prom_init(void)
+ 	}
+ #endif
+ 
++	/*
++	 * RouterBOOT uses "Board" kernel parameter instead of "board" since
++	 * version 3.41 (or so). Replace the first character of the parameter
++	 * to keep board detection working.
++	 */
++	c = strstr(arcs_cmdline, "Board=");
++	if (c)
++		c[0] = 'b';
++
+ 	if (strstr(arcs_cmdline, "board=750Gr3") ||
+ 	    strstr(arcs_cmdline, "board=750i") ||
+ 	    strstr(arcs_cmdline, "board=750-hb") ||