i915: use kzalloc to allocate intel_output for lvds

Better to initialize all the struct fields to 0.  Also more consistent with
other output init routines.

linux-core/intel_lvds.c

@@ -387,7 +387,7 @@ void intel_lvds_init(struct drm_device *dev)
 	u32 lvds;
 	int pipe;
 
-	intel_output = kmalloc(sizeof(struct intel_output), GFP_KERNEL);
+	intel_output = kzalloc(sizeof(struct intel_output), GFP_KERNEL);
 	if (!intel_output) {
 		return;
 	}