Patch for rk322x TPL is not merged, and only SPL is available now,
enable the sdram driver in SPL first. We should update back to TPL
after TPL is enabled for rk322x.
Signed-off-by: NKever Yang <kever.yang@rock-chips.com>
Reviewed-by: NPhilipp Tomsich <philipp.tomsich@theobroma-systems.com>