console: add support for disabling timestamps
console: add support for disabling timestamps

People may want to disable timestamps. Add a command to do that.

BUG=none
BRANCH=none
TEST=none

Change-Id: I702c41a214367b6c58f3d9b932310e1bb7e08b95
Signed-off-by: Mary Ruthven <81380f3403fed74252e92df3ed012a1819ec6296@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/1586588
Reviewed-by: Tim Wawrzynczak <86444811eee8c2cb29e29a251d7a069e64ccc665@chromium.org>

coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec