power: supply: sysfs: Move power_supply_show_enum_with_available() up

power: supply: sysfs: Move power_supply_show_enum_with_available() up

Move power_supply_show_enum_with_available() higher up in
the power_supply_sysfs.c file.

This is a preparation patch to avoid needing a forward declaration
when replacing power_supply_show_usb_type() with it later on.

This commit only moves the function, there are no changes to it.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20240831142039.28830-6-hdegoede@redhat.com
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>