drm/i915: Remove PCH type checks from ironlake_crtc_compute_clock()

The checks were added in commit 5dc5298b ("drm/i915: add proper
CPU/PCH checks to crtc_mode_set functions") in a time when there was
doubts on what PCHs would be supported by HSW. There are similar checks
for PCH type in intel_detect_pch() and the function pointers are
initialized based on platform/pch information, so the removed WARN can't
ever be reached.

v2: Rebase without patch that drops lvds downclock code. (Ville)
Signed-off-by: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1458576016-30348-8-git-send-email-ander.conselvan.de.oliveira@intel.com

drivers/gpu/drm/i915/intel_display.c

@@ -8797,7 +8797,6 @@ static uint32_t ironlake_compute_dpll(struct intel_crtc *intel_crtc,
 static int ironlake_crtc_compute_clock(struct intel_crtc *crtc,
 				       struct intel_crtc_state *crtc_state)
 {
-	struct drm_device *dev = crtc->base.dev;
 	intel_clock_t clock, reduced_clock;
 	u32 dpll = 0, fp = 0, fp2 = 0;
 	bool has_reduced_clock = false;
@@ -8809,9 +8808,6 @@ static int ironlake_crtc_compute_clock(struct intel_crtc *crtc,
 
 	is_lvds = intel_pipe_will_have_type(crtc_state, INTEL_OUTPUT_LVDS);
 
-	WARN(!(HAS_PCH_IBX(dev) || HAS_PCH_CPT(dev)),
-	     "Unexpected PCH type %d\n", INTEL_PCH_TYPE(dev));
-
 	if (!crtc_state->clock_set) {
 		if (!ironlake_compute_clocks(&crtc->base, crtc_state, &clock,
 					     &has_reduced_clock,