nfs: Add missing release on error in nfs_lock_and_join_requests()

Call nfs_release_request() on this error path before returning.

Fixes: c3f22357 ("nfs: fold nfs_folio_find_and_lock_request into nfs_lock_and_join_requests")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Link: https://lore.kernel.org/r/3aaaa3d5-1c8a-41e4-98c7-717801ddd171@stanley.mountain


Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>