io_uring: fix invalid hybrid polling ctx leaks

It has already allocated the ctx by the point where it checks the hybrid
poll configuration, plain return leaks the memory.

Fixes: 01ee194d ("io_uring: add support for hybrid IOPOLL")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Reviewed-by: Anuj Gupta <anuj20.g@samsung.com>
Link: https://lore.kernel.org/r/b57f2608088020501d352fcdeebdb949e281d65b.1731468230.git.asml.silence@gmail.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>