sparc32: Pass -mcpu=v7 explicitly to gcc.

We should be agnostic to what gcc happens to be generating by default.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

arch/sparc/Makefile

@@ -30,7 +30,7 @@ export BITS    := 32
 UTS_MACHINE    := sparc
 
 #KBUILD_CFLAGS += -g -pipe -fcall-used-g5 -fcall-used-g7
-KBUILD_CFLAGS += -m32 -pipe -mno-fpu -fcall-used-g5 -fcall-used-g7
+KBUILD_CFLAGS += -m32 -mcpu=v7 -pipe -mno-fpu -fcall-used-g5 -fcall-used-g7
 KBUILD_AFLAGS += -m32 -Wa,-Av8
 
 #LDFLAGS_vmlinux = -N -Ttext 0xf0004000