cryptolib: put constant arrays in rodata segment

The SHA256 constants and some algo definitions are currently in the
.data segment, this wastes precious RAM on the EC where read-only data
are stored in flash only.

BUG=chrome-os-partner:12271
TEST=sudo emerge vboot_reference &&
emerge-daisy vboot_reference vboot_reference-firmware chromeos-ec
and manually check the content of the .data segment in the EC binary.

Change-Id: I67b8c0f2843312651e8ac287cea2f8cb5f075453
Reviewed-on: https://gerrit.chromium.org/gerrit/29273
Tested-by: Vincent Palatin <vpalatin@chromium.org>
Reviewed-by: Randall Spangler <rspangler@chromium.org>
Commit-Ready: Vincent Palatin <vpalatin@chromium.org>
4 files changed