xf86SetSingleMode tries to resize all crtcs to match the selected mode. When
a CRTC has no matching mode, it now disables the CRTC (instead of crashing).
Also, poke the RandR extension when xf86SetSingleMode is done so that
appropriate events can be delivered, and so that future RandR queries return
correct information.
(cherry picked from commit dc6c4f6989)
This code comes from the intel driver, so there's no history in this tree.
As the crtc/output-based mode selection code uses ddc, the ddc and i2c
modules have been merged into the server. Attempts to load them are safely
ignored now.
