powerpc: Make ARCH=powerpc the default for 32-bit ppc

This makes ARCH=powerpc the default on 32-bit powerpc machines,
where uname -m returns ppc, as well as on 64-bit powerpc machines.
Most people who would be likely to build their own kernels on
32-bit powerpc machines would be using powermacs or CHRP machines,
both of which are supported with ARCH=powerpc now. Embedded ppc
developers whose ports haven't been moved over to arch/powerpc
yet will have to explicitly set ARCH=ppc now.

Signed-off-by: Paul Mackerras <[e-mail]>

Makefile

···
 SUBARCH := $(shell uname -m | sed -e s/i.86/i386/ -e s/sun4u/sparc64/ \
 				  -e s/arm.*/arm/ -e s/sa110/arm/ \
 				  -e s/s390x/s390/ -e s/parisc64/parisc/ \
-				  -e s/ppc64/powerpc/ )
+				  -e s/ppc.*/powerpc/ )
 
 # Cross compiling and selecting different set of gcc/bin-utils
 # ---------------------------------------------------------------------------