[PATCH] powerpc: Merge cacheflush.h and cache.h

The ppc32 and ppc64 versions of cacheflush.h were almost identical.
The two versions of cache.h are fairly similar, except for a bunch of
register definitions in the ppc32 version which probably belong better
elsewhere.  This patch, therefore, merges both headers.  Notable
points:
	- there are several functions in cacheflush.h which exist only
on ppc32 or only on ppc64.  These are handled by #ifdef for now, but
these should probably be consolidated, along with the actual code
behind them later.
	- Confusingly, both ppc32 and ppc64 have a
flush_dcache_range(), but they're subtly different: it uses dcbf on
ppc32 and dcbst on ppc64, ppc64 has a flush_inval_dcache_range() which
uses dcbf.  These too should be merged and consolidated later.
	- Also flush_dcache_range() was defined in cacheflush.h on
ppc64, and in cache.h on ppc32.  In the merged version it's in
cacheflush.h
	- On ppc32 flush_icache_range() is a normal function from
misc.S.  On ppc64, it was wrapp...