security: make security_file_set_fowner, f_setown and __f_setown void return

security_file_set_fowner always returns 0, so make it f_setown and
__f_setown void return functions and fix up the error handling in the
callers.

Cc: linux-security-module@vger.kernel.org
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

security/smack/smack_lsm.c

@@ -1390,12 +1390,11 @@ static int smack_mmap_file(struct file *file,
  * Returns 0
  * Further research may be required on this one.
  */
-static int smack_file_set_fowner(struct file *file)
+static void smack_file_set_fowner(struct file *file)
 {
 	struct smack_known *skp = smk_of_current();
 
 	file->f_security = skp->smk_known;
-	return 0;
 }
 
 /**