RDMA/bnxt_re: Protect the PD table bitmap

Syncrhonization is required to avoid simultaneous allocation
of the PD. Add a new mutex lock to handle allocation from
the PD table.

Signed-off-by: Kashyap Desai <kashyap.desai@broadcom.com>
Signed-off-by: Selvin Xavier <selvin.xavier@broadcom.com>
Link: https://lore.kernel.org/r/1692032419-21680-2-git-send-email-selvin.xavier@broadcom.com


Signed-off-by: Leon Romanovsky <leon@kernel.org>