pinctrl: rockchip: fix pinmux reset in rockchip_pmx_set

rockchip_pmx_set reset all pinmuxs in group to 0 in the case of error,
add missing bank data retrieval in that code to avoid setting mux on
unexpected pins.

Fixes: 14797189

 ("pinctrl: rockchip: add return value to rockchip_set_mux")
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Huang-Huang Bao <i@eh5.me>
Link: https://lore.kernel.org/r/20240606125755.53778-5-i@eh5.me
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>