Extend the "rdma sys" command to display whether RDMA
monitoring is supported.

RDMA monitoring is not supported in mlx4 because it does
not use the ib_device_set_netdev() API, which sends the
RDMA events.

Example output for kernel where monitoring is supported:
$ rdma sys show
netns shared privileged-qkey off monitor on copy-on-fork on

Example output for kernel where monitoring is not supported:
$ rdma sys show
netns shared privileged-qkey off monitor off copy-on-fork on
Signed-off-by: Chiara Meiohas <cmeiohas@nvidia.com>
Signed-off-by: Michael Guralnik <michaelgur@nvidia.com>
Link: https://patch.msgid.link/20240909173025.30422-8-michaelgur@nvidia.comSigned-off-by: Leon Romanovsky <leon@kernel.org>