Updates to the following:
BUILD_ARCH
SOURCE_MIRROR_FETCH
TARGET_PREFIX
SDK_PREFIX
SDK_SYS (I added this one new).
(From yocto-docs rev: ad5f9b56dc912783b415b30604456bd5071f9721)
Signed-off-by: Scott Rifenbark <scott.m.rifenbark@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>