RDMA/qedr: Use the common mmap API

Remove all functions related to mmap from qedr and use the common API.

Link: https://lore.kernel.org/r/20191030094417.16866-7-michal.kalderon@marvell.com


Signed-off-by: Ariel Elior <ariel.elior@marvell.com>
Signed-off-by: Michal Kalderon <michal.kalderon@marvell.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>