drm/i915: reuse the sdvo tv clock adjustment in ilk mode_set

Jesse extracted this nice helper in his i9xx_crtc_mode_set refactor,
but we have the identical code in ironlake_ccrtc_mode_set. And that
function is huge, so extracting some code full of magic numbers is
always nice.

Noticed while trying to get a handle on our dp clock code.
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-Off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_display.c

@@ -4395,25 +4395,10 @@ static int ironlake_crtc_mode_set(struct drm_crtc *crtc,
 						    &clock,
 						    &reduced_clock);
 	}
-	/* SDVO TV has fixed PLL values depend on its clock range,
-	   this mirrors vbios setting. */
-	if (is_sdvo && is_tv) {
-		if (adjusted_mode->clock >= 100000
-		    && adjusted_mode->clock < 140500) {
-			clock.p1 = 2;
-			clock.p2 = 10;
-			clock.n = 3;
-			clock.m1 = 16;
-			clock.m2 = 8;
-		} else if (adjusted_mode->clock >= 140500
-			   && adjusted_mode->clock <= 200000) {
-			clock.p1 = 1;
-			clock.p2 = 10;
-			clock.n = 6;
-			clock.m1 = 12;
-			clock.m2 = 8;
-		}
-	}
+
+	if (is_sdvo && is_tv)
+		i9xx_adjust_sdvo_tv_clock(adjusted_mode, &clock);
+
 
 	/* FDI link */
 	pixel_multiplier = intel_mode_get_pixel_multiplier(adjusted_mode);