Use wide color modes with external displays

A prior code cleanup made it obvious that wide color modes were only
being used for the primary display. This patch allows external displays
to use wide color modes, and adds a requested TODO to update a variable
name.

Bug: None
Test: Builds
Change-Id: Iec262e51674a2a2f7fcfc9177c7bfbf0b1a860e3
1 file changed