pasemi_mac: add local skb alignment

Add local SKB alignment to pasemi_mac, since ppc64 in general has it at 0
because of design flaws in some of the IBM server bridge chips. However,
for PWRficient doing the unaligned copies is more expensive than doing
unaligned DMA so make sure the data is aligned instead.
Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Jeff Garzik <jeff@garzik.org>