msm: mdss: dsi: set backlight handle to NULL in error case

Set pwm backlight handle to NULL during dsi panel
pwm configuration when it fails with an error.

Change-Id: Ia28ab3728888731999c61672faf1bd2f5be1965f
Signed-off-by: Chirag Khurana <ckhurana@codeaurora.org>
diff --git a/drivers/video/fbdev/msm/mdss_dsi_panel.c b/drivers/video/fbdev/msm/mdss_dsi_panel.c
index 7eb8c70..7ee3ab9 100644
--- a/drivers/video/fbdev/msm/mdss_dsi_panel.c
+++ b/drivers/video/fbdev/msm/mdss_dsi_panel.c
@@ -46,6 +46,7 @@
 	if (ctrl->pwm_bl == NULL || IS_ERR(ctrl->pwm_bl)) {
 		pr_err("%s: Error: lpg_chan=%d pwm request failed",
 				__func__, ctrl->pwm_lpg_chan);
+		ctrl->pwm_bl = NULL;
 	}
 	ctrl->pwm_enabled = 0;
 }