kernfs: mount: Remove unnecessary ‘NULL’ values from knparent

knparent is assigned first, so it does not need to initialize the
assignment.

Signed-off-by: Li zeming <[e-mail]>
Acked-by: Tejun Heo <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

fs/kernfs/mount.c

···
 				  struct super_block *sb)
 {
 	struct dentry *dentry;
-	struct kernfs_node *knparent = NULL;
+	struct kernfs_node *knparent;
 
 	BUG_ON(sb->s_op != &kernfs_sops);