RDMA/usnic: fix set-but-not-unused variable 'flags' warning

Remove unused local variable 'flag'
without any logic changes.

Fixes: e3cf00d0 ("IB/usnic: Add Cisco VIC low-level hardware driver")
Signed-off-by: Zeng Heng <zengheng4@huawei.com>
Link: https://lore.kernel.org/r/20220929031200.4060891-1-zengheng4@huawei.com


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