rockchip: Use common bss and stack addresses on RK3308

rockchip: Use common bss and stack addresses on RK3308

Currently the following memory layout is typically used on RK3308:
[    0, 256K) - SPL binary
[ 256K,   2M) - TF-A / reserved
[   -X,   4M) - SPL pre-reloc stack (SPL_STACK)
[  -8K,   4M)   - pre-reloc malloc heap (SPL_SYS_MALLOC_F_LEN)
[   4M,  +8K) - SPL bss (SPL_BSS_START_ADDR, SPL_BSS_MAX_SIZE)
[   6M,   +X) - U-Boot proper binary (TEXT_BASE)
[   -X,   8M) - U-Boot proper pre-reloc stack (CUSTOM_SYS_INIT_SP_ADDR)
[  -8K,   8M)   - pre-reloc malloc heap (SYS_MALLOC_F_LEN)
[   -X,  12M) - SPL reloc stack (SPL_STACK_R_ADDR)
[  11M,  12M)   - reloc malloc heap (SPL_STACK_R_MALLOC_SIMPLE_LEN)

SPL can safely load U-Boot proper + FDT to [6M, 8M-8K) with this layout.

Migrate to use common bss, stack and malloc heap size and addresses to
remove this size limitation and extend the malloc heap size being used.

Signed-off-by: Jonas Karlman <jonas@kwiboo.se>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>