[PATCH] powerpc: work around sparse warnings in cputable.h

Christoph noticed that sparse warned about all the enum tags in cuptable.h
that had values that required them to be type log. (enum tags are ints
according to the standard.)

This patch attempts to fix them in the least intrusive way possible by
turning them all into #defines except for the 32 bit CPU_FTRS_POSSIBLE and
CPU_FTRS_ALWAYS which are hard to construct that way.  This works because
these last two contain no bits above 2^31.
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>