kill useless checks for sb->s_op == NULL

never is...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/inode.c b/fs/inode.c
index 43566d1..cbdcab8 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -1331,7 +1331,7 @@
 
 	WARN_ON(inode->i_state & I_NEW);
 
-	if (op && op->drop_inode)
+	if (op->drop_inode)
 		drop = op->drop_inode(inode);
 	else
 		drop = generic_drop_inode(inode);