Add pinctrl driver for RK3506.
Imported from vendor U-Boot linux-6.1-stan-rkr6 tag with adjustments
to use regmap_update_bits().
Signed-off-by: Ye Zhang <ye.zhang@rock-chips.com>
Signed-off-by: Jonas Karlman <jonas@kwiboo.se>
Tested-by: Aaron Griffith <aargri@gmail.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>