RDMA/rxe: Fix mw bind to allow any consumer key portion

RDMA/rxe: Fix mw bind to allow any consumer key portion

The current implementation of rxe_check_bind_mw() in rxe_mw.c is incorrect
since it requires the new key portion provided by the mw consumer to be
different than the previous key portion. This is not required by the
IBA. Remove the test.

Link: https://lore.kernel.org/linux-rdma/fb4614e7-4cac-0dc7-3ef7-766dfd10e8f2@gmail.com/
Fixes: 73185602f840 ("Add support for bind MW work requests")
Link: https://lore.kernel.org/r/20220714204619.13396-1-rpearsonhpe@gmail.com
Signed-off-by: Bob Pearson <rpearsonhpe@gmail.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>