[PATCH] libata-core.c: fix parameter bug on kunmap_atomic() calls

Fix incorrect pointer usage on two calls to kunmap_atomic().
This seems to happen a lot, because kunmap() wants the struct page *,
whereas kunmap_atomic() instead wants the mapped virtual address.

Signed-off-by: Mark Lord <liml@rtr.ca>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>