[PATCH 2/2] power: supply: Fix build error when CONFIG_POWER_SUPPLY is not enabled.

[Ray Chi]

The build error happens when CONFIG_POWER_SUPPLY is not enabled.

h8300-linux-ld: drivers/usb/dwc3/gadget.o: in function `.L59':
>> gadget.c:(.text+0x655): undefined reference to `power_supply_set_property'

Fixes: 99288de36020 ("usb: dwc3: add an alternate path in vbus_draw callback")
Reported-by: kernel test robot <lkp@xxxxxxxxx>
Signed-off-by: Ray Chi <raychi@xxxxxxxxxx>
---
 include/linux/power_supply.h | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/include/linux/power_supply.h b/include/linux/power_supply.h
index 81a55e974feb..b495b4374cd0 100644
--- a/include/linux/power_supply.h
+++ b/include/linux/power_supply.h
@@ -426,9 +426,16 @@ static inline int power_supply_is_system_supplied(void) { return -ENOSYS; }
 extern int power_supply_get_property(struct power_supply *psy,
 			    enum power_supply_property psp,
 			    union power_supply_propval *val);
+#if IS_ENABLED(CONFIG_POWER_SUPPLY)
 extern int power_supply_set_property(struct power_supply *psy,
 			    enum power_supply_property psp,
 			    const union power_supply_propval *val);
+#else
+static inline int power_supply_set_property(struct power_supply *psy,
+			    enum power_supply_property psp,
+			    const union power_supply_propval *val)
+{ return 0; }
+#endif
 extern int power_supply_property_is_writeable(struct power_supply *psy,
 					enum power_supply_property psp);
 extern void power_supply_external_power_changed(struct power_supply *psy);
-- 
2.31.0.291.g576ba9dcdaf-goog