scarlet: Turn on CONFIG_TABLET_MODE_SWITCH
scarlet: Turn on CONFIG_TABLET_MODE_SWITCH

BUG=b:62594071
BRANCH=scarlet
TEST=boot scarlet and confirm it's in tablet mode

Change-Id: I85cc53bb66d70acc9f5c77bd7c428447159dabb0
Reviewed-on: https://chromium-review.googlesource.com/534937
Commit-Ready: Philip Chen <3ee404f9ef892bc3fda6e6a76e65843b5fa44db2@chromium.org>
Tested-by: Philip Chen <3ee404f9ef892bc3fda6e6a76e65843b5fa44db2@chromium.org>
Reviewed-by: Alexandru M Stan <1784cbba6d7675b1eba55eaefe41c7672ad9da3b@chromium.org>

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