RDMA/irdma: Replace deprecated strncpy

RDMA/irdma: Replace deprecated strncpy

`strncpy` is deprecated for use on NUL-terminated destination strings [1]
and as such we should prefer more robust and less ambiguous string
interfaces.

A suitable replacement is `strscpy_pad` due to the fact that it
guarantees NUL-termination on the destination buffer.

It is unclear to me whether `i40iw_client.name` requires NUL-padding but
have opted to keep the NUL-padding behavior that strncpy provides to
ensure no functional change.

Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings
Link: https://github.com/KSPP/linux/issues/90
Cc: linux-hardening@vger.kernel.org
Signed-off-by: Justin Stitt <justinstitt@google.com>
Link: https://lore.kernel.org/r/20230921-strncpy-drivers-infiniband-hw-irdma-i40iw_if-c-v1-1-22d87aef7186@google.com
Signed-off-by: Leon Romanovsky <leon@kernel.org>