libpayload: arch/mips: Add basic MIPS architecture support

Add the basic build infrastructure and architectural support
required to build for targets using the MIPS architecture.
This will require the addition of cache maintenance.

BUG=chrome-os-partner:31438
TEST=tested on Pistachio FPGA with Depthcharge as payload;
     successfully executed payload.
BRANCH=none

Change-Id: I75cfd0536860b6d84b53a567940fe6668d9b2cbb
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: 758c8cb9a6846e6ca32be409ec5f7a888ac9c888
Original-Signed-off-by: Ionela Voinescu <ionela.voinescu@imgtec.com>
Original-Change-Id: I0b9af983bf5032335a519ce2510a0b3aca082edf
Original-Reviewed-on: https://chromium-review.googlesource.com/219740
Original-Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/8741
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
38 files changed