pinctrl/rockchip: add error handling for pull/drive register getters

[ Upstream commit 42573ab ]

Add error handling for the pull and driver register getters in preparation
for RK3588 support.

Signed-off-by: Sebastian Reichel <[email protected]>
Reviewed-by: Heiko Stübner <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Linus Walleij <[email protected]>
Stable-dep-of: 31b62a9 ("pinctrl: rockchip: fix reading pull type on rk3568")
Signed-off-by: Sasha Levin <[email protected]>

Author: sre