drm/i915/dp: don't mention eDP bpp clamping if it doesn't affect bpp

This is useful with the follow-up patch that frobs
dev_priv->vbt.edp_bpp, and the value no longer comes directly from
VBT.
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_dp.c

@@ -822,10 +822,11 @@ intel_dp_compute_config(struct intel_encoder *encoder,
 	/* Walk through all bpp values. Luckily they're all nicely spaced with 2
 	 * bpc in between. */
 	bpp = pipe_config->pipe_bpp;
-	if (is_edp(intel_dp) && dev_priv->vbt.edp_bpp) {
+	if (is_edp(intel_dp) && dev_priv->vbt.edp_bpp &&
+	    dev_priv->vbt.edp_bpp < bpp) {
 		DRM_DEBUG_KMS("clamping bpp for eDP panel to BIOS-provided %i\n",
 			      dev_priv->vbt.edp_bpp);
-		bpp = min_t(int, bpp, dev_priv->vbt.edp_bpp);
+		bpp = dev_priv->vbt.edp_bpp;
 	}
 
 	for (; bpp >= 6*3; bpp -= 2*3) {