[ARM] 2970/1: Use -mtune=arm1136j-s when building for CPU_V6 targets

Patch from George G. Davis

When building for CPU_V6 targets, we should use -mtune=arm1136j-s rather
than -mtune=strongarm but fall back to the later in case someone is
using an older toolchain (although they should really upgrade instead).
Signed-off-by: George G. Davis <gdavis@mvista.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/Makefile

@@ -53,7 +53,7 @@ tune-$(CONFIG_CPU_ARM926T)	:=-mtune=arm9tdmi
 tune-$(CONFIG_CPU_SA110)	:=-mtune=strongarm110
 tune-$(CONFIG_CPU_SA1100)	:=-mtune=strongarm1100
 tune-$(CONFIG_CPU_XSCALE)	:=$(call cc-option,-mtune=xscale,-mtune=strongarm110) -Wa,-mcpu=xscale
-tune-$(CONFIG_CPU_V6)		:=-mtune=strongarm
+tune-$(CONFIG_CPU_V6)		:=$(call cc-option,-mtune=arm1136j-s,-mtune=strongarm)
 
 # Need -Uarm for gcc < 3.x
 CFLAGS_ABI	:=$(call cc-option,-mapcs-32,-mabi=apcs-gnu) $(call cc-option,-mno-thumb-interwork,)