pinctrl: Fix return value about devm_platform_ioremap_resource()

pinctrl: Fix return value about devm_platform_ioremap_resource()

[ Upstream commit b5d9ff10dca49f4d4b7846c3751c6bec50d07375 ]

When call function devm_platform_ioremap_resource(), we should use IS_ERR()
to check the return value and return PTR_ERR() if failed.

Fixes: 4b024225c4a8 ("pinctrl: use devm_platform_ioremap_resource() to simplify code")
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Link: https://lore.kernel.org/r/1590234326-2194-1-git-send-email-yangtiezhu@loongson.cn
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>