rockchip: rk322x: update MACRO for back-to-brom

The MACRO has been update after:
ee14d29d rockchip: back-to-bootrom: split BACK_TO_BOOTROM for TPL/SPL
We need to update the C code for it.

Signed-off-by: Kever Yang <kever.yang@rock-chips.com>
Acked-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>