brcm47xx: explicitely mention MIPS to avoid confusion

And while at it, fix the nomenclature, BCM947xx/953xx refer to specific boards,
while BCM47xx/BCM53xx refer to chip identification number.

Signed-off-by: Florian Fainelli <florian@openwrt.org>

SVN-Revision: 39841

target/linux/brcm47xx/Makefile

@@ -8,7 +8,7 @@ include $(TOPDIR)/rules.mk
 
 ARCH:=mipsel
 BOARD:=brcm47xx
-BOARDNAME:=Broadcom BCM947xx/953xx
+BOARDNAME:=Broadcom BCM47xx/53xx (MIPS)
 FEATURES:=squashfs usb pcmcia
 MAINTAINER:=Hauke Mehrtens <hauke@hauke-m.de>