riscv: separately define stack locations at different stages

BOOTBLOCK/ROMSTAGE run in CAR/scratchpad. When RAMSTAGE begins
execution will enable cache, then CAR will disappear. So the
Stack will be separated.

Change-Id: I37a0c1928052cabf61ba5c25b440363b75726782
Signed-off-by: Xiang Wang <wxjstz@126.com>
Reviewed-on: https://review.coreboot.org/28383
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
2 files changed