io_uring/rsrc: call io_free_node() on io_sqe_buffer_register() failure

io_uring/rsrc: call io_free_node() on io_sqe_buffer_register() failure

io_sqe_buffer_register() currently calls io_put_rsrc_node() if it fails
to fully set up the io_rsrc_node. io_put_rsrc_node() is more involved
than necessary, since we already know the reference count will reach 0
and no io_mapped_ubuf has been attached to the node yet.

So just call io_free_node() to release the node's memory. This also
avoids the need to temporarily set the node's buf pointer to NULL.

Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Link: https://lore.kernel.org/r/20250228235916.670437-3-csander@purestorage.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>