rockchip: Use common bss and stack addresses on PX30

See commit 008ba0d5 ("rockchip: Add common default bss and stack
addresses") for memory layout. This migrates PX30 to use the new layout,
except for TPL. Indeed, PX30 is extremely limited in SRAM, so we need to
be extra careful about what goes into the TPL and how much we can
allocate there, so let's keep the current value for
TPL_SYS_MALLOC_F_LEN (already present in the PX30-specific Kconfig, from
an earlier commit).

This will allow us to use the same memory layout on one more Rockchip
SoC, which is always a nice thing. Additionally, this will make it
easier to fix U-Boot proper pre-reloc running out of memory on PX30 in a
subsequent commit.

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