drm/i915: Fix cursor 'cpp' in watermark calculatins for old platforms

The watermark code for the old platforms (g4x and older) uses the
primary plane cpp when computing cursor watermarks. To keep the fix
simple let's just hardcode cpp=4 for the cursor on those platforms
since that's all we support.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170421181432.15216-8-ville.syrjala@linux.intel.comReviewed-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>

drivers/gpu/drm/i915/intel_pm.c

@@ -768,7 +768,7 @@ static void pineview_update_wm(struct intel_crtc *unused_crtc)
 		/* cursor SR */
 		wm = intel_calculate_wm(clock, &pineview_cursor_wm,
 					pineview_display_wm.fifo_size,
-					cpp, latency->cursor_sr);
+					4, latency->cursor_sr);
 		reg = I915_READ(DSPFW3);
 		reg &= ~DSPFW_CURSOR_SR_MASK;
 		reg |= FW_WM(wm, CURSOR_SR);
@@ -786,7 +786,7 @@ static void pineview_update_wm(struct intel_crtc *unused_crtc)
 		/* cursor HPLL off SR */
 		wm = intel_calculate_wm(clock, &pineview_cursor_hplloff_wm,
 					pineview_display_hplloff_wm.fifo_size,
-					cpp, latency->cursor_hpll_disable);
+					4, latency->cursor_hpll_disable);
 		reg = I915_READ(DSPFW3);
 		reg &= ~DSPFW_HPLL_CURSOR_MASK;
 		reg |= FW_WM(wm, HPLL_CURSOR);
@@ -842,7 +842,7 @@ static bool g4x_compute_wm0(struct drm_i915_private *dev_priv,
 	/* Use the large buffer method to calculate cursor watermark */
 	line_time_us = max(htotal * 1000 / clock, 1);
 	line_count = (cursor_latency_ns / line_time_us + 1000) / 1000;
-	entries = line_count * crtc->base.cursor->state->crtc_w * cpp;
+	entries = line_count * crtc->base.cursor->state->crtc_w * 4;
 	tlb_miss = cursor->fifo_size*cursor->cacheline_size - hdisplay * 8;
 	if (tlb_miss > 0)
 		entries += tlb_miss;
@@ -930,7 +930,7 @@ static bool g4x_compute_srwm(struct drm_i915_private *dev_priv,
 	*display_wm = entries + display->guard_size;
 
 	/* calculate the self-refresh watermark for display cursor */
-	entries = line_count * cpp * crtc->base.cursor->state->crtc_w;
+	entries = line_count * 4 * crtc->base.cursor->state->crtc_w;
 	entries = DIV_ROUND_UP(entries, cursor->cacheline_size);
 	*cursor_wm = entries + cursor->guard_size;
 
@@ -1736,7 +1736,7 @@ static void i965_update_wm(struct intel_crtc *unused_crtc)
 			      entries, srwm);
 
 		entries = (((sr_latency_ns / line_time_us) + 1000) / 1000) *
-			cpp * crtc->base.cursor->state->crtc_w;
+			4 * crtc->base.cursor->state->crtc_w;
 		entries = DIV_ROUND_UP(entries,
 					  i965_cursor_wm_info.cacheline_size);
 		cursor_sr = i965_cursor_wm_info.fifo_size -