pinctrl: Remove redundant null pointer checks in pinctrl_remove_device_debugfs()

Since the debugfs_create_dir() never returns a null pointer, checking
the return value for a null pointer is redundant, and using IS_ERR is
safe enough.

Signed-off-by: Li Zetao <[e-mail]>
Link: https://lore.kernel.org/[e-mail]
Signed-off-by: Linus Walleij <[e-mail]>

drivers/pinctrl/core.c

···
 static void pinctrl_init_debugfs(void)
 {
 	debugfs_root = debugfs_create_dir("pinctrl", NULL);
-	if (IS_ERR(debugfs_root) || !debugfs_root) {
+	if (IS_ERR(debugfs_root)) {
 		pr_warn("failed to create debugfs directory\n");
 		debugfs_root = NULL;
 		return;