power: ccadc: Initialize voltage_uv to fix compilation warning

Fixes following compilation warning:
pm8xxx-ccadc.c:552: warning: 'voltage_uv' may be used uninitialized

Change-Id: Ib84e2733d91af0fd12dd73662079c5e564e8bffb
Signed-off-by: Trilok Soni <tsoni@codeaurora.org>
diff --git a/drivers/power/pm8xxx-ccadc.c b/drivers/power/pm8xxx-ccadc.c
index c95fd93..65bc654 100644
--- a/drivers/power/pm8xxx-ccadc.c
+++ b/drivers/power/pm8xxx-ccadc.c
@@ -549,7 +549,7 @@
 
 int pm8xxx_ccadc_get_battery_current(int *bat_current_ua)
 {
-	int voltage_uv, rc;
+	int voltage_uv = 0, rc;
 
 	rc = ccadc_get_rsense_voltage(&voltage_uv);
 	if (rc) {