coffeecake: Enable CONFIG_LTO
coffeecake: Enable CONFIG_LTO

Enable CONFIG_LTO to free up flash space.

BUG=None
TEST=Build
BRANCH=None

Signed-off-by: Rob Barnes <3ced0940a2329ce70499686f01d3d60685ec66ed@google.com>
Change-Id: I12b399005e55b004ffb312fef05484ee14fdfbad
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3136036
Reviewed-by: Diana Z <cb2016afc7183e5356c690dc63b4ba817470501a@chromium.org>

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