Use <powerpc/oea/bat.h> exclusively and remove <machine/bat.h> and
<powerpc/bat.h>. Remove unneeded <machine/cpufunc.h>. To insure
1:1 correspondence of <powerpc/FOO.h> to <machine/FOO.h> include
"../../powerpc/include/Makefile" in "arch/FOO/include/Makefile".
Incororpate <byte_swap.h> into <bswap.h> and then byte_swap.h
