drm/i915: Remove BUG_ON call in vlv_enable_pll

Do some further clean up based on the initial review of
drm/i915: Separate cherryview from valleyview.

In this case remove the BUG_ON call in vlv_enable_pll().

v2: Also remove the BUG_ON call in chv_enable_pll(). (Ville)

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Wayne Boyer <wayne.boyer@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1449529362-18193-1-git-send-email-wayne.boyer@intel.com
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

drivers/gpu/drm/i915/intel_display.c

@@ -1607,9 +1607,6 @@ static void vlv_enable_pll(struct intel_crtc *crtc,
 
 	assert_pipe_disabled(dev_priv, crtc->pipe);
 
-	/* No really, not for ILK+ */
-	BUG_ON(!IS_VALLEYVIEW(dev_priv->dev));
-
 	/* PLL is protected by panel, make sure we can write it */
 	if (IS_MOBILE(dev_priv->dev))
 		assert_panel_unlocked(dev_priv, crtc->pipe);
@@ -1647,8 +1644,6 @@ static void chv_enable_pll(struct intel_crtc *crtc,
 
 	assert_pipe_disabled(dev_priv, crtc->pipe);
 
-	BUG_ON(!IS_CHERRYVIEW(dev_priv->dev));
-
 	mutex_lock(&dev_priv->sb_lock);
 
 	/* Enable back the 10bit clock to display controller */