IB/uverbs: fix the typo of optional

Fix the typo of optional in the function of UVERBS_HANDLER.

Signed-off-by: Deming Wang <wangdeming@inspur.com>
Link: https://lore.kernel.org/r/20221006161456.2998-1-wangdeming@inspur.com


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