leds: leds-pm8xxx: Add CABC support for backlight control

Content adaptive backlight control (CABC) support is needed to
control backlight by external PWM.  It can be enabled by setting
"cabc_en = true" in the platform data wled_cfg structure.

CRs-fixed: 379347

Signed-off-by: Amy Maloche <amaloche@codeaurora.org>
(cherry picked from commit c366d5bfc380183e1c4f9877b2c8558098bd4281)

Change-Id: Iae7940d25d8754ab539d5ce1fa3f78972b5222d1
Signed-off-by: Sudhir Sharma <sudsha@codeaurora.org>
diff --git a/include/linux/leds-pm8xxx.h b/include/linux/leds-pm8xxx.h
index ab530b5..a5959af 100644
--- a/include/linux/leds-pm8xxx.h
+++ b/include/linux/leds-pm8xxx.h
@@ -85,6 +85,7 @@
  *  @dig_mod_gen_en - digital module generator
  *  @cs_out_en - current sink output enable
  *  @op_fdbck - selection of output as feedback for the boost
+ *  @cabc_en - enable cabc for backlight pwm control
  */
 struct wled_config_data {
 	u8	num_strings;
@@ -95,6 +96,7 @@
 	bool	dig_mod_gen_en;
 	bool	cs_out_en;
 	bool	op_fdbck;
+	bool	cabc_en;
 };
 
 /**