modify g781.c/.h to g78x.c/.h to suppor both G781/G782 temp sensor
based on CONFIG_TEMP_SENSOR_G781 or CONFIG_TEMP_SENSOR_G782
BUG=none
BRANCH=none
TEST=make buildall; able to get temperature data on board with G782
Change-Id: Ia32c85e9964bfd7c0c5263f04368bc001a27fe10
Signed-off-by: Kevin K Wong <kevin.k.wong@intel.com>
Reviewed-on: https://chromium-review.googlesource.com/334228
Reviewed-by: Shawn N <shawnn@chromium.org>