drm/i915/mst: Continue state updates even if AUX writes fail.

We are too late in the enabling sequence to back out cleanly, not updating
state tracking variables, like intel_dp->active_mst_links in this
instance, results in incorrect behaviour further along.

v2: Fixed int v/s bool comparison

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Nathan Ciobanu <nathan.d.ciobanu@linux.intel.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=107281Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Reviewed-by: Nathan Ciobanu <nathan.d.ciobanu@linux.intel.com>
Tested-by: Nathan Ciobanu <nathan.d.ciobanu@linux.intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180718171943.3246-2-dhinakaran.pandiyan@intel.com

drivers/gpu/drm/i915/intel_dp_mst.c

@@ -241,11 +241,8 @@ static void intel_mst_pre_enable_dp(struct intel_encoder *encoder,
 				       connector->port,
 				       pipe_config->pbn,
 				       pipe_config->dp_m_n.tu);
-	if (ret == false) {
+	if (!ret)
 		DRM_ERROR("failed to allocate vcpi\n");
-		return;
-	}
-
 
 	intel_dp->active_mst_links++;
 	temp = I915_READ(DP_TP_STATUS(port));