drm-backend: removing the restriction of exclusively presenting in

plane-assignment

in `drm_output_propose_state`, we are removing the restriction of exclusively
present for view to be assigned on a plane, as in the case of cloning outputs,
no views would fit this condition. Now one view can be assigned to different
planes on different outputs.

Signed-off-by: xichen zhou <sichem.zh@gmail.com>
3 jobs for indep_crtc_clone in 1 minute and 32 seconds (queued for 1 second)
latest
Status Job ID Name Coverage
  Container Prep
passed #2694002
container_prep

00:00:26

 
  Build
passed #2694003
build-native-meson-default-options

00:01:06

passed #2694004
build-native-meson-no-gl-renderer

00:00:36