exynos5420/kirby: necessary updates for DRAM

This updates DRAM usage for Kirby so that we can actually
use the available 3.5GB:

- The chips on Kirby have 16 row address lines.
- CONFIG_DRAM_SIZE_MB should be 3584 (4096-512).
- We use 2 DMC channels on Kirby (each with 2GB).

Signed-off-by: David Hendricks <dhendrix@chromium.org>
BUG=chrome-os-partner:22144
BRANCH=none
TEST=built and booted (sorta) on Kirby, mem test succeeds

Change-Id: I86d1a96d0d1a028587f7655f8de5a2e52165e9d2
Reviewed-on: https://chromium-review.googlesource.com/167489
Commit-Queue: David Hendricks <dhendrix@chromium.org>
Tested-by: David Hendricks <dhendrix@chromium.org>
Reviewed-by: ron minnich <rminnich@chromium.org>
3 files changed