rockchip: ringneck-px30: get closer to other Theobroma defconfigs

RK3588 Jaguar and Tiger, and RK3399 Puma use standard boot with the full
feature set, so let's do that as well for PX30 Ringneck.

Disable support for unused OSes as Linux is the primary target.

Enable a bunch of commands:
 - boot/bootd
 - erofs
 - gpio
 - iminfo
 - imxtract
 - itest
 - pmic
 - regulator
 - sleep
 - squashfs

that could be useful and are also found in Jaguar and Tiger defconfigs.

Signed-off-by: Quentin Schulz <quentin.schulz@cherry.de>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>