drm/msm: select PM_OPP

Otherwise, if nothing else enabled selects it, dev_pm_opp_of_add_table()
will return -ENOTSUPP.

Fixes: e2af8b6b ("drm/msm: gpu: Use OPP tables if we can")
Signed-off-by: Rob Clark <robdclark@gmail.com>

drivers/gpu/drm/msm/Kconfig

@@ -13,6 +13,7 @@ config DRM_MSM
 	select QCOM_SCM
 	select SND_SOC_HDMI_CODEC if SND_SOC
 	select SYNC_FILE
+	select PM_OPP
 	default y
 	help
 	  DRM/KMS driver for MSM/snapdragon.