rockchip: rk3328: rock64 - fix gen3 SPL hang

Use the same approach as ROC-RK3328-CC which enables SPL GPIO,
pinctl and regulator support. This allows the gen3 board to
boot through SPL and does not break gen2 in the process.

Signed-off-by: Kurt Miller <kurt@intricatesoftware.com>
Acked-by: Matwey V. Kornilov <matwey.kornilov@gmail.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>