IB/ehca: Fix sg_page() fallout

More fallout from sg_page changes:

drivers/infiniband/hw/ehca/ehca_mrmw.c: In function 'ehca_set_pagebuf_user1':
drivers/infiniband/hw/ehca/ehca_mrmw.c:1779: error: 'struct scatterlist' has no member named 'page'
drivers/infiniband/hw/ehca/ehca_mrmw.c: In function 'ehca_check_kpages_per_ate':
drivers/infiniband/hw/ehca/ehca_mrmw.c:1835: error: 'struct scatterlist' has no member named 'page'
drivers/infiniband/hw/ehca/ehca_mrmw.c: In function 'ehca_set_pagebuf_user2':
drivers/infiniband/hw/ehca/ehca_mrmw.c:1870: error: 'struct scatterlist' has no member named 'page'

Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>