drm/i915: Restore lost "Initialized i915" welcome message

A side effect of removing the midlayer from driver loading was the loss
of a useful message announcing to userspace that i915 had successfully
started, e.g.:

	[drm] Initialized i915 1.6.0 20160425 for 0000:00:02.0 on minor 0

Reported-by: Timo Aaltonen <tjaalton@ubuntu.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Fixes: 8f460e2c78 ("drm/i915: Demidlayer driver loading")
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: drm-intel-fixes@lists.freedesktop.org
Link: http://patchwork.freedesktop.org/patch/msgid/20160825072314.17402-1-chris@chris-wilson.co.uk
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_drv.c

@@ -1255,6 +1255,11 @@ int i915_driver_load(struct pci_dev *pdev, const struct pci_device_id *ent)
 
 	intel_runtime_pm_enable(dev_priv);
 
+	/* Everything is in place, we can now relax! */
+	DRM_INFO("Initialized %s %d.%d.%d %s for %s on minor %d\n",
+		 driver.name, driver.major, driver.minor, driver.patchlevel,
+		 driver.date, pci_name(pdev), dev_priv->drm.primary->index);
+
 	intel_runtime_pm_put(dev_priv);
 
 	return 0;