drm/i915: Move FBC init and cleanup calls to modeset functions

Although FBC helps save power it do not belongs to power management
also the cleanup was placed in i915_driver_unload() also not a good
place. intel_modeset_init()/intel_modeset_cleanup() are better places
also this will help make easy disable features that depends in
display being enabled in driver.

Cc: Jani Nikula <[e-mail]>
Cc: Ville Syrjälä <[e-mail]>
Signed-off-by: José Roberto de Souza <[e-mail]>
Reviewed-by: Ville Syrjälä <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/i915/i915_drv.c

···
 	i915_reset_error_state(dev_priv);
 
 	i915_gem_fini(dev_priv);
-	intel_fbc_cleanup_cfb(dev_priv);
 
 	intel_power_domains_fini_hw(dev_priv);
 

drivers/gpu/drm/i915/intel_display.c

···
 
 	intel_init_quirks(dev_priv);
 
+	intel_fbc_init(dev_priv);
+
 	intel_init_pm(dev_priv);
 
 	/*
···
 	intel_teardown_gmbus(dev_priv);
 
 	destroy_workqueue(dev_priv->modeset_wq);
+
+	intel_fbc_cleanup_cfb(dev_priv);
 }
 
 /*

drivers/gpu/drm/i915/intel_pm.c

···
 /* Set up chip specific power management-related functions */
 void intel_init_pm(struct drm_i915_private *dev_priv)
 {
-	intel_fbc_init(dev_priv);
-
 	/* For cxsr */
 	if (IS_PINEVIEW(dev_priv))
 		i915_pineview_get_mem_freq(dev_priv);