drm/msm/dpu: switch RM to use crtc_id rather than enc_id for allocation

Up to now the driver has been using encoder to allocate hardware
resources. Switch it to use CRTC id in preparation for the next step.

Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Jessica Zhang <quic_jesszhan@quicinc.com>
Patchwork: https://patchwork.freedesktop.org/patch/637503/
Link: https://lore.kernel.org/r/20250214-concurrent-wb-v6-3-a44c293cf422@quicinc.com


Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>