drm/i915/lvds: separate border enable readout from panel fitter

The LVDS border enable is independent from the panel fitter. Move the
readout of the "border bits" from i9xx_get_pfit_config() to
intel_lvds_get_config(), where it will be read if LVDS is enabled even
if the panel fitter is not.

This fixes the state checker warning:

[drm:intel_pipe_config_compare [i915]] *ERROR* mismatch in
gmch_pfit.lvds_border_bits (expected 0x00008000, found 0x00000000)

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: drm-intel-fixes@lists.freedesktop.org
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=87632
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Tested-by: Sitsofe Wheeler <sitsofe@yahoo.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1461933243-2140-1-git-send-email-jani.nikula@intel.com
(cherry picked from commit a0cbe6a3f1c0e86342965430b4a775b5d35b416b)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

drivers/gpu/drm/i915/intel_display.c

@@ -7988,9 +7988,6 @@ static void i9xx_get_pfit_config(struct intel_crtc *crtc,
 
 	pipe_config->gmch_pfit.control = tmp;
 	pipe_config->gmch_pfit.pgm_ratios = I915_READ(PFIT_PGM_RATIOS);
-	if (INTEL_INFO(dev)->gen < 5)
-		pipe_config->gmch_pfit.lvds_border_bits =
-			I915_READ(LVDS) & LVDS_BORDER_ENABLE;
 }
 
 static void vlv_crtc_clock_get(struct intel_crtc *crtc,

drivers/gpu/drm/i915/intel_lvds.c

@@ -123,6 +123,10 @@ static void intel_lvds_get_config(struct intel_encoder *encoder,
 
 	pipe_config->base.adjusted_mode.flags |= flags;
 
+	if (INTEL_INFO(dev)->gen < 5)
+		pipe_config->gmch_pfit.lvds_border_bits =
+			tmp & LVDS_BORDER_ENABLE;
+
 	/* gen2/3 store dither state in pfit control, needs to match */
 	if (INTEL_INFO(dev)->gen < 4) {
 		tmp = I915_READ(PFIT_CONTROL);