[PATCH] sata_mv: endian fix

This fixes a byte-swap issue on PPC, found by Zang Roy-r61911
on the powerpc platform.  His original patch also had some other
platform-specific changes in #ifdef's, but I'm not sure yet how to
incorporate them.  Look for another patch for those (soon).

Signed-off-by: Mark Lord <liml@rtr.ca>
Signed-off-by: Jeff Garzik <jeff@garzik.org>