rockchip: pine64: rockpro64: migrate to rockchip_early_misc_init_r

rockchip: pine64: rockpro64: migrate to rockchip_early_misc_init_r

Only setup_iodomain() differs from the original misc_init_r from
Rockchip mach code, so let's use rockchip_early_misc_init_r instead of
reimplementing the whole misc_init_r from Rockchip.

Cc: Quentin Schulz <foss+uboot@0leil.net>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
Reviewed-by: Dragan Simic <dsimic@manjaro.org>
Reviewed-by: Peter Robinson <pbrobinson@gmail.com>
Signed-off-by: Quentin Schulz <quentin.schulz@theobroma-systems.com>