ARMv7/Exynos: Fix memory location assumptions

This patch cleans out a lot of unused variables in the
ARM Kconfig files and introduces CONFIG_RAMSTAGE_BASE
which is similar to CONFIG_RAMBASE on x86.
This gets rid of the hard coded assumption that on ARM
coreboot is always executed at the lowest DRAM address.
But in fact, this might not be true because we might want
coreboot to live at the end of RAM, or in SRAM

BUG=none
BRANCH=none
TEST=successfully booted on pit.

Change-Id: I03e992645f9eb730e39a521aa21f702959311f74
Signed-off-by: Stefan Reinauer <reinauer@google.com>
Reviewed-on: https://chromium-review.googlesource.com/168645
Reviewed-by: David Hendrix <dhendrix@chromium.org>
Tested-by: David Hendrix <dhendrix@chromium.org>
5 files changed