scarlet: Add support for CONFIG_EMULATED_SYSRQ
scarlet: Add support for CONFIG_EMULATED_SYSRQ

BRANCH=none
BUG=b:69981636
TEST=sysrq stuff on console, and try buttons

Change-Id: I198eae9444febcd2d341e23d0e8098d40fc10bed
Signed-off-by: Brian Norris <67059238af8e1945c40edb274ce1d51ba595dbf3@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/802626
Reviewed-by: Furquan Shaikh <6be5c96c464778f89679b1062a2e0a6af93d2aa5@chromium.org>

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