firmware_ECWriteProtect: Unprotect EC before testing

If EC is already write protected, unprotect it before starting write
protection test.

BUG=chrome-os-partner:15835
TEST=Write protect EC and start the test. Check the test unprotect EC
and pass.

Change-Id: Ia5252629ea19b670e4fce0365a0d1c2382ad1001
Signed-off-by: Vic Yang <victoryang@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/37346
Reviewed-by: Tom Wai-Hong Tam <waihong@chromium.org>
1 file changed