power: pm8921-charger: add POWER_SUPPLY_PROP_ONLINE for USB and AC

Add POWER_SUPPLY_PROP_ONLINE for non battery supply like USB and AC
so that it can be used by power supply driver.

Signed-off-by: Willie Ruan <wruan@codeaurora.org>
diff --git a/drivers/power/pm8921-charger.c b/drivers/power/pm8921-charger.c
index 1151461..e250d54 100644
--- a/drivers/power/pm8921-charger.c
+++ b/drivers/power/pm8921-charger.c
@@ -476,6 +476,7 @@
 
 static enum power_supply_property pm_power_props[] = {
 	POWER_SUPPLY_PROP_PRESENT,
+	POWER_SUPPLY_PROP_ONLINE,
 };
 
 static char *pm_power_supplied_to[] = {
@@ -490,6 +491,7 @@
 
 	switch (psp) {
 	case POWER_SUPPLY_PROP_PRESENT:
+	case POWER_SUPPLY_PROP_ONLINE:
 		if (psy->type == POWER_SUPPLY_TYPE_MAINS) {
 			chip = container_of(psy, struct pm8921_chg_chip,
 							dc_psy);