rockchip: theobroma-systems: puma: migrate to rockchip_early_misc_init_r

Only setup_iodomain() and setup_boottargets differ 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>
Signed-off-by: Quentin Schulz <quentin.schulz@theobroma-systems.com>