io_uring: fix bad indentation for setup flags if statement

smatch complains about this:

smatch warnings:
io_uring/io_uring.c:2741 io_uring_sanitise_params() warn: if statement not indented

hence fix it up.

Link: https://lore.kernel.org/all/202601231651.HeTmPS8C-lkp@intel.com/
Fixes: 5247c034a67f ("io_uring: introduce non-circular SQ")
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/r/202601231651.HeTmPS8C-lkp@intel.com/
Signed-off-by: Jens Axboe <axboe@kernel.dk>