NFS: drop __exit from nfs_exit_keyring

Otherwise built-in NFS can lead to sectіon mismatches.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20250714062450.1468117-1-hch@lst.de
Fixes: 87268f7 ("nfs: create a kernel keyring")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Author: Christoph Hellwig

fs/nfs/inode.c

@@ -2663,7 +2663,7 @@ static int __init nfs_init_keyring(void)
 	return PTR_ERR_OR_ZERO(nfs_keyring);
 }
 
-static void __exit nfs_exit_keyring(void)
+static void nfs_exit_keyring(void)
 {
 	key_put(nfs_keyring);
 }