ipq806x: increase kernel partition size for the Netgear Nighthawk X4 R7500

Starting with kernel 4.14 and gcc 7, the kernel doesn't fit into the
2 MB reserved for the kernel partition by the OEM firmware anymore.

This patch increases the kernel partition from 2 MB to 4 MB, at the
expense of the rootfs, for all supported kernels.

WARNING: This breaks sysupgrade! Flashing a firmware containing this
changed partitioning from an older image with 2 MB reserved for the
kernel partion requires the tftp recovery procedure, thereby losing
all settings.

This change follows the functional example of the Netgear r7800, but
has not been runtime tested on a Netgear Nighthawk X4 R7500

Signed-off-by: Stefan Lippers-Hollmann <s.l-h@gmx.de>
Cc: Jonas Gorski <jonas.gorski@gmail.com>

target/linux/ipq806x/files-4.14/arch/arm/boot/dts/qcom-ipq8064-r7500.dts

@@ -216,12 +216,12 @@
 
 					kernel@1340000 {
 						label = "kernel";
-						reg = <0x1340000 0x0200000>;
+						reg = <0x1340000 0x0400000>;
 					};
 
-					ubi@1540000 {
+					ubi@1740000 {
 						label = "ubi";
-						reg = <0x1540000 0x1800000>;
+						reg = <0x1740000 0x1600000>;
 					};
 
 					netgear@2d40000 {

target/linux/ipq806x/files-4.9/arch/arm/boot/dts/qcom-ipq8064-r7500.dts

@@ -216,12 +216,12 @@
 
 					kernel@1340000 {
 						label = "kernel";
-						reg = <0x1340000 0x0200000>;
+						reg = <0x1340000 0x0400000>;
 					};
 
-					ubi@1540000 {
+					ubi@1740000 {
 						label = "ubi";
-						reg = <0x1540000 0x1800000>;
+						reg = <0x1740000 0x1600000>;
 					};
 
 					netgear@2d40000 {

target/linux/ipq806x/image/Makefile

@@ -119,7 +119,7 @@ TARGET_DEVICES += netgear_d7800
 define Device/netgear_r7500
 	$(call Device/DniImage)
 	DEVICE_DTS := qcom-ipq8064-r7500
-	KERNEL_SIZE := 2097152
+	KERNEL_SIZE := 4194304
 	NETGEAR_BOARD_ID := R7500
 	NETGEAR_HW_ID := 29764841+0+128+256+3x3+4x4
 	BLOCKSIZE := 128k