cifs: remove redundant duplicated assignment of pointer 'node'

Node is assigned twice to rb_first(root), first during declaration
time and second after a taking a spin lock, so we have a duplicated
assignment.  Remove the first assignment because it is redundant and
also not protected by the spin lock.

Cleans up clang warning:
fs/cifs/connect.c:4435:18: warning: Value stored to 'node' during
its initialization is never read
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NSteve French <smfrench@gmail.com>
Reviewed-by: NRonnie Sahlberg <lsahlber@redhat.com>

fs/cifs/connect.c

@@ -4432,7 +4432,7 @@ cifs_prune_tlinks(struct work_struct *work)
 	struct cifs_sb_info *cifs_sb = container_of(work, struct cifs_sb_info,
 						    prune_tlinks.work);
 	struct rb_root *root = &cifs_sb->tlink_tree;
-	struct rb_node *node = rb_first(root);
+	struct rb_node *node;
 	struct rb_node *tmp;
 	struct tcon_link *tlink;