RDMA: During rereg_mr ensure that REREG_ACCESS is compatible

RDMA: During rereg_mr ensure that REREG_ACCESS is compatible

If IB_MR_REREG_ACCESS changes from RO to RW then the umem has to be
re-evaluated to ensure it is properly pinned as RW. Since the umem is
hidden inside each driver's mr struct add a ib_umem_check_rereg() function
that each driver has to call before processing IB_MR_REREG_ACCESS.

mlx4 has to retain its duplicate ib_access_writable check because it
implements IB_MR_REREG_ACCESS | IB_MR_REREG_TRANS by changing both items
in place sequentially while the MR is live, so it will continue to not
support this combination.

Cc: stable@vger.kernel.org
Fixes: b40656aa7d55 ("RDMA/umem: remove FOLL_FORCE usage")
Link: https://patch.msgid.link/r/0-v1-06fb1a2d6cf5+107-rereg_access_jgg@nvidia.com
Reported-by: Philip Tsukerman <philiptsukerman@gmail.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>