disp: msm: sde: calculate line_time once during modeset

Calculate line_time once during modeset and allow
each plane to use it instead of calculating for each frame.
It also simplifies the line_time calculation for
command mode display.

Change-Id: I94ce29eec94bfdbee9016fbf93378661ebf79c03
Signed-off-by: Dhaval Patel <pdhaval@codeaurora.org>

msm/sde/sde_encoder.c

@@ -4336,7 +4336,7 @@ void sde_encoder_helper_get_pp_line_count(struct drm_encoder *drm_enc,
 	}
 }
 
-void sde_encoder_helper_get_transfer_time(struct drm_encoder *drm_enc,
+void sde_encoder_get_transfer_time(struct drm_encoder *drm_enc,
 			u32 *transfer_time_us)
 {
 	struct sde_encoder_virt *sde_enc;