soc/intel/cannonlake: Disable RTC write protect

The cannonlake FSP enables PchLockDownRtcMemoryLock by default, but we
need this memory to be writable.  We normally over-ride this in the
SoC chip init code, so we'll do the same on cannonlake.

BUG=b:71722386
BRANCH=none
TEST=Filled /dev/nvram with 0xff and 0x00 bytes to verify we can flip
all the bits.

Change-Id: I7cdd4abc2b3795d7dd82236fbe3c112428ee882b
Signed-off-by: Caveh Jalali <caveh@chromium.org>
Reviewed-on: https://review.coreboot.org/25069
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Vincent Palatin <vpalatin@chromium.org>
1 file changed