disp: msm: add support for display early wakeup

Display clocks and IRQs are disabled during idle state
on command mode for power saving, and will be enabled
when a new frame commits to display driver. But enable
display clocks and IRQs will cause some latency.
So add a new SDE custom IOCTL for user-space to early wake
up display before first frame commits to kernel.

Change-Id: I6ca0188d321c4964f29c46e588b64d06b9634c59
Signed-off-by: Lei Chen <chenlei@codeaurora.org>

msm/msm_kms.h

@@ -100,6 +100,8 @@ struct msm_kms_funcs {
 	void (*set_encoder_mode)(struct msm_kms *kms,
 				 struct drm_encoder *encoder,
 				 bool cmd_mode);
+	void (*display_early_wakeup)(struct drm_device *dev,
+				const int32_t connector_id);
 	/* pm suspend/resume hooks */
 	int (*pm_suspend)(struct device *dev);
 	int (*pm_resume)(struct device *dev);