disp: msm: move vblank enable and disable to crtc hooks

Upstream now prefers to utilize vblank enable and disable
through crtc hooks rather than drm driver. Remove
calls from kms vblank enable/disbale.

Change-Id: Ic6911838f14f93a0d277b7bdc2c1968270ec25a2
Signed-off-by: Samantha Tran <samtran@codeaurora.org>
Signed-off-by: Nilaan Gunabalachandran <ngunabal@codeaurora.org>

msm/msm_kms.h

@@ -57,8 +57,6 @@ struct msm_kms_funcs {
 	int (*irq_postinstall)(struct msm_kms *kms);
 	void (*irq_uninstall)(struct msm_kms *kms);
 	irqreturn_t (*irq)(struct msm_kms *kms);
-	int (*enable_vblank)(struct msm_kms *kms, struct drm_crtc *crtc);
-	void (*disable_vblank)(struct msm_kms *kms, struct drm_crtc *crtc);
 	/* modeset, bracketing atomic_commit(): */
 	void (*prepare_fence)(struct msm_kms *kms,
 			struct drm_atomic_state *state);