drm/i915/dsb: Use intel_color_uses_dsb()

Use intel_color_uses_dsb() instead of open coding it in
intel_vblank_evade_init(). Make the logic around DSB a bit
more isolated from the rest of the code.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240531114101.19994-5-ville.syrjala@linux.intel.com


Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>