drm/i915/glk: Fix DSI "*ERROR* ULPS is still active" messages

The sequence in glk_dsi_device_ready() enters ULPS then waits until it is
*not* active to then disable it. The correct sequence according to the
spec is to enter ULPS then wait until the GLK_ULPS_NOT_ACTIVE bit is
zero, i.e., ULPS is active, and then disable ULPS.

Fixing the condition gets rid of the following spurious error messages:

[drm:glk_dsi_device_ready [i915]] *ERROR* ULPS is still active

Fixes: 4644848369c0 ("drm/i915/glk: Add MIPIIO Enable/disable sequence")
Cc: Deepak M <m.deepak@intel.com>
Cc: Madhav Chauhan <madhav.chauhan@intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Daniel Vetter <daniel.vetter@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: intel-gfx@lists.freedesktop.org
Cc: <drm-intel-fixes@lists.freedesktop.org>
Signed-off-by: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Reviewed-by: Madhav Chauhan <madhav.chauhan@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170428080222.6147-1-ander.conselvan.de.oliveira@intel.com

drivers/gpu/drm/i915/intel_dsi.c

@@ -410,11 +410,10 @@ static void glk_dsi_device_ready(struct intel_encoder *encoder)
 		val |= (ULPS_STATE_ENTER | DEVICE_READY);
 		I915_WRITE(MIPI_DEVICE_READY(port), val);
 
-		/* Wait for ULPS Not active */
+		/* Wait for ULPS active */
 		if (intel_wait_for_register(dev_priv,
-				MIPI_CTRL(port), GLK_ULPS_NOT_ACTIVE,
-				GLK_ULPS_NOT_ACTIVE, 20))
-			DRM_ERROR("ULPS is still active\n");
+				MIPI_CTRL(port), GLK_ULPS_NOT_ACTIVE, 0, 20))
+			DRM_ERROR("ULPS not active\n");
 
 		/* Exit ULPS */
 		val = I915_READ(MIPI_DEVICE_READY(port));