drm/msm/disp/dpu: reset the datapath after timing engine disable

Reset the datapath after disabling the timing gen, such that
it can start on a clean slate when the intf is enabled back.
This was a recommended sequence from the DPU HW programming guide.

Signed-off-by: Vinod Polimera <[e-mail]>
Reviewed-by: Dmitry Baryshkov <[e-mail]>
Patchwork: https://patchwork.freedesktop.org/patch/524729/
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Dmitry Baryshkov <[e-mail]>

drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_vid.c

···
 		}
 	}
 
+	dpu_encoder_helper_phys_cleanup(phys_enc);
 	phys_enc->enable_state = DPU_ENC_DISABLED;
 }