drm/i915: Add intel_bios_cleanup() function

Add an intel_bios_cleanup() function to act as counterpart of
intel_bios_init() and move the cleanup of vbt related resources there,
putting it in the same file as the allocation.

Changed in v2:
-While touching the code anyways, remove the unnecessary:
 if (dev_priv->vbt.child_dev) done before kfree(dev_priv->vbt.child_dev)

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180214082151.25015-1-hdegoede@redhat.com
diff --git a/drivers/gpu/drm/i915/intel_bios.c b/drivers/gpu/drm/i915/intel_bios.c
index aa4df65..ea1ed84 100644
--- a/drivers/gpu/drm/i915/intel_bios.c
+++ b/drivers/gpu/drm/i915/intel_bios.c
@@ -1611,6 +1611,21 @@ void intel_bios_init(struct drm_i915_private *dev_priv)
 }
 
 /**
+ * intel_bios_cleanup - Free any resources allocated by intel_bios_init()
+ * @dev_priv: i915 device instance
+ */
+void intel_bios_cleanup(struct drm_i915_private *dev_priv)
+{
+	kfree(dev_priv->vbt.child_dev);
+	dev_priv->vbt.child_dev = NULL;
+	dev_priv->vbt.child_dev_num = 0;
+	kfree(dev_priv->vbt.sdvo_lvds_vbt_mode);
+	dev_priv->vbt.sdvo_lvds_vbt_mode = NULL;
+	kfree(dev_priv->vbt.lfp_lvds_vbt_mode);
+	dev_priv->vbt.lfp_lvds_vbt_mode = NULL;
+}
+
+/**
  * intel_bios_is_tv_present - is integrated TV present in VBT
  * @dev_priv:	i915 device instance
  *