exynos5420: ddr3: Cleanup init to use constants for directcmd

The old ddr3_mem_ctrl_init() for exynos5420 had hardcoded constants
for accessing directcmd registers.  Modify to use #defines where
possible.

BRANCH=pit
BUG=chrome-os-partner:20775
TEST=Compare of u-boot-spl.wrapped.bin before and after shows no
change

[dianders: split from init cleanup patch]

Change-Id: I4e3f25ba8aae96e2d9ee4b494bc3aa3e4039e191
Signed-off-by: Akshay Saraswat <akshay.s@samsung.com>
Signed-off-by: Doug Anderson <dianders@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/65616
Reviewed-by: Vadim Bendebury <vbendeb@chromium.org>
1 file changed