disp: msm: sde: avoid returning vsync count for cwb encoder

In CWB use case along with suspend commit, the function
drm_crtc_funcs.get_vblank_counter returns a zero vsync count
value. This causes blocking of drm_crtc_funcs.disable_vblank,
leading to a wait for vsync timeout while disabling the encoder.
hence clear a cwb encoder mask in encoder disable and set it
while performing mode set.

Change-Id: Ic994aa0a86faf48e2b25955cf6fe12166fe9d328
Signed-off-by: Akash Gajjar <quic_agajjar@quicinc.com>

msm/sde/sde_encoder.c

@@ -3123,6 +3123,7 @@ static void sde_encoder_virt_mode_set(struct drm_encoder *drm_enc,
 				sde_crtc_state->cached_cwb_enc_mask);
 		sde_crtc_state->cwb_enc_mask = sde_crtc_state->cached_cwb_enc_mask;
 		sde_encoder_set_clone_mode(drm_enc, crtc_state);
+		sde_crtc->cached_encoder_mask |= drm_encoder_mask(drm_enc);
 	}
 
 	/* reserve dynamic resources now, indicating non test-only */