drm/vc4: kms: Assign a FIFO to enabled CRTCs instead of active

drm/vc4: kms: Assign a FIFO to enabled CRTCs instead of active

The HVS has three FIFOs that can be assigned to a number of PixelValves
through a mux.

However, changing that FIFO requires that we disable and then enable the
pixelvalve, so we want to assign FIFOs to all the enabled CRTCs, and not
just the active ones.

Fixes: 87ebcd42fb7b ("drm/vc4: crtc: Assign output to channel automatically")
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
[hoegeun.kwon: Needed to fix page flip issue of dual hdmi.]
Signed-off-by: Hoegeun Kwon <hoegeun.kwon@samsung.com>
Change-Id: Id418d321e3cfc9b992bd1868e8084d9f8694a46e