rockchip: Kconfig: enable SPL support for rk3328

Enable SPL support and some related option in Kconfig.

Signed-off-by: Kever Yang <kever.yang@rock-chips.com>
[cherry picked from https://github.com/rockchip-linux/u-boot/commit/430b01462bf3f24aaf7920ae2587a6943c39ab5d

 with minor modifications]
Signed-off-by: Matwey V. Kornilov <matwey.kornilov@gmail.com>