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 <lizetao1@huawei.com>
Link: https://lore.kernel.org/20240903143812.2005071-1-lizetao1@huawei.com


Signed-off-by: Linus Walleij <linus.walleij@linaro.org>