powerpc: Move Power Macintosh drivers to generic byteswappers

ppc has special instruction forms to efficiently load and store values
in non-native endianness.  These can be accessed via the arch-specific
{ld,st}_le{16,32}() inlines in arch/powerpc/include/asm/swab.h.

However, gcc is perfectly capable of generating the byte-reversing
load/store instructions when using the normal, generic cpu_to_le*() and
le*_to_cpu() functions eaning the arch-specific functions don't have much
point.

Worse the "le" in the names of the arch specific functions is now
misleading, because they always generate byte-reversing forms, but some
ppc machines can now run a little-endian kernel.

To start getting rid of the arch-specific forms, this patch removes them
from all the old Power Macintosh drivers, replacing them with the
generic byteswappers.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>