drm/i915: Remove unneeded hack now for CDCLK

No need to bump up CDCLK now, as it is now correctly
calculated, accounting for DBuf BW as BSpec says.

Reviewed-by: Manasi Navare <manasi.d.navare@intel.com>
Signed-off-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200519131117.17190-8-stanislav.lisovskiy@intel.com

Author: StanFox1984

drivers/gpu/drm/i915/display/intel_cdclk.c

@@ -2070,18 +2070,6 @@ int intel_crtc_compute_min_cdclk(const struct intel_crtc_state *crtc_state)
 	/* Account for additional needs from the planes */
 	min_cdclk = max(intel_planes_min_cdclk(crtc_state), min_cdclk);
 
-	/*
-	 * HACK. Currently for TGL platforms we calculate
-	 * min_cdclk initially based on pixel_rate divided
-	 * by 2, accounting for also plane requirements,
-	 * however in some cases the lowest possible CDCLK
-	 * doesn't work and causing the underruns.
-	 * Explicitly stating here that this seems to be currently
-	 * rather a Hack, than final solution.
-	 */
-	if (IS_TIGERLAKE(dev_priv))
-		min_cdclk = max(min_cdclk, (int)crtc_state->pixel_rate);
-
 	if (min_cdclk > dev_priv->max_cdclk_freq) {
 		drm_dbg_kms(&dev_priv->drm,
 			    "required cdclk (%d kHz) exceeds max (%d kHz)\n",