monitor-manager: only support underscan when mode allows it

Underscan should only be available for certain modes; in particular, it
should only be available for HDMI displays with a compatible resolution.

https://bugzilla.gnome.org/show_bug.cgi?id=767804

!549
11 jobs for !549 with gbsneto/underscan
detached
Status Job ID Name Coverage
  Review
passed #280146
check-commit-log

00:05:01

failed #280145
check-commit-log

failed #280144
check-commit-log

failed #280141
check-commit-log

 
  Build
passed #280142
build-mutter

00:03:04

 
  Test
failed #287930
test-mutter

failed #281951
test-mutter

failed #281950
test-mutter

failed #281949
test-mutter

failed #281948
test-mutter

failed #280143
test-mutter

 
Name Stage Failure
failed
test-mutter Test There has been a missing dependency failure
No job trace