[PATCH] sky2: fix FIFO DMA alignment problems

The Yukon2 chip FIFO has a problem recovering from a pause frame
if the receive buffer is not aligned. The workaround is to just
leave receive buffer at original alignment, which will make IP
header unaligned. Rework receive logic for clarity.

Need to ignore receive overrun interrupts (or mac hangs).

These fixes make the sky2 driver generally usable.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>