RDMA/bnxt_re: Add check for path mtu in modify_qp

RDMA/bnxt_re: Add check for path mtu in modify_qp

When RDMA app configures path MTU, add a check in modify_qp verb
to make sure that it doesn't go beyond interface MTU. If this
check fails, driver will fail the modify_qp verb.

Fixes: 1ac5a4047975 ("RDMA/bnxt_re: Add bnxt_re RoCE driver")
Reviewed-by: Kalesh AP <kalesh-anakkur.purayil@broadcom.com>
Signed-off-by: Saravanan Vajravel <saravanan.vajravel@broadcom.com>
Signed-off-by: Selvin Xavier <selvin.xavier@broadcom.com>
Link: https://patch.msgid.link/20241211083931.968831-3-kalesh-anakkur.purayil@broadcom.com
Signed-off-by: Leon Romanovsky <leon@kernel.org>