drm/vc4: kms: Don't disable the muxing of an active CRTC

drm/vc4: kms: Don't disable the muxing of an active CRTC

The current HVS muxing code will consider the CRTCs in a given state to
setup their muxing in the HVS, and disable the other CRTCs muxes.

However, it's valid to only update a single CRTC with a state, and in this
situation we would mux out a CRTC that was enabled but left untouched by
the new state.

Fix this by considering all the CRTCs in the state and the ones with a
state and active.

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: Idb6e79214f52e470e9fcf5a0579873402c631eb2