ARM: shmobile: always build rcar setup for armv7

In a combined ARMv6/v7 kernel, the setup-rcar-gen2.c cannot
currently be compiled correctly because it uses the isb
instruction that is not available on ARMv6. Adding the
-march=armv7-a flag lets the compiler know that it is safe
to build this file for ARMv7.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Acked-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>

arch/arm/mach-shmobile/Makefile

@@ -36,6 +36,7 @@ cpu-y				:= platsmp.o headsmp.o
 
 # Shared SoC family objects
 obj-$(CONFIG_ARCH_RCAR_GEN2)	+= setup-rcar-gen2.o platsmp-apmu.o $(cpu-y)
+CFLAGS_setup-rcar-gen2.o	+= -march=armv7-a
 
 # SMP objects
 smp-y				:= $(cpu-y)