drm/i915: use correct power domain for csr loading

Grabbing a runtime pm reference with intel_runtime_pm_get will only
prevent device D3. But dmc firmware is required even earlier (namely
for the skl power well 2).

Hence we need to grab a rpm reference higher up in the hierarchy. For
simplicity just grab the _INIT display power well. That's a bit too
much, but since the firmware loading task should completely fairly
quickly this won't be a real problem really.

Cc: Damien Lespiau <damien.lespiau@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Sunil Kamath <sunil.kamath@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Signed-off-by: Animesh Manna <animesh.manna@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Tested-by: Daniel Stone <daniels@collabora.com> # SKL
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1446069547-24760-3-git-send-email-imre.deak@intel.com

drivers/gpu/drm/i915/intel_csr.c

@@ -405,7 +405,7 @@ static void finish_csr_load(const struct firmware *fw, void *context)
 
 out:
 	if (fw_loaded) {
-		intel_runtime_pm_put(dev_priv);
+		intel_display_power_put(dev_priv, POWER_DOMAIN_INIT);
 
 		DRM_INFO("Finished loading %s (v%u.%u)\n",
 			 dev_priv->csr.fw_path,
@@ -452,7 +452,7 @@ void intel_csr_ucode_init(struct drm_device *dev)
 	 * Obtain a runtime pm reference, until CSR is loaded,
 	 * to avoid entering runtime-suspend.
 	 */
-	intel_runtime_pm_get(dev_priv);
+	intel_display_power_get(dev_priv, POWER_DOMAIN_INIT);
 
 	/* CSR supported for platform, load firmware */
 	ret = request_firmware_nowait(THIS_MODULE, true, csr->fw_path,