power: supply: Fix build error when CONFIG_POWER_SUPPLY is not enabled.

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: 99288de3 ("usb: dwc3: add an alternate path in vbus_draw callback")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Ray Chi <raychi@google.com>
Link: https://lore.kernel.org/r/20210327182809.1814480-3-raychi@google.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>