frameworks: set default expanded desktop style

On a fresh boot, a user can add an expanded desktop tile. They can also
add it to their power menu. But until they go into Display -> Expanded
desktop style and set it to something other than disabled, it won't show
up anywhere.

Since the user has to toggle expanded desktop, let's use a sensible
default and avoid the extra step.

Change-Id: I7fbe8c58d85d14c227d5e237260eee4181beafed
Signed-off-by: Roman Birg <roman@cyngn.com>