[MIPS] Add support for BCM47XX CPUs.

Note that the BCM4710 does not support the wait instruction, this
is not a mistake in the code.
    
It originally comes from the OpenWrt patches.
    
Cc: Michael Buesch <mb@bu3sch.de>
Cc: Felix Fietkau <nbd@openwrt.org>
Cc: Florian Schirmer <jolt@tuxbox.org>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/Makefile b/arch/mips/Makefile
index 6dcdbfb..7b936ed 100644
--- a/arch/mips/Makefile
+++ b/arch/mips/Makefile
@@ -535,6 +535,13 @@
 load-$(CONFIG_SIBYTE_BIGSUR)	:= 0xffffffff80100000
 
 #
+# Broadcom BCM47XX boards
+#
+core-$(CONFIG_BCM47XX)		+= arch/mips/bcm47xx/
+cflags-$(CONFIG_BCM47XX)	+= -Iinclude/asm-mips/mach-bcm47xx
+load-$(CONFIG_BCM47XX)		:= 0xffffffff80001000
+
+#
 # SNI RM
 #
 core-$(CONFIG_SNI_RM)		+= arch/mips/sni/