power: supply: Remove unused set_charged method

The previous patches in this series removed the only caller
and only setter of this method.

Remove it.

Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Link: https://lore.kernel.org/r/20250307230225.128775-4-linux@treblig.org
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

Author: Dr. David Alan Gilbert

include/linux/power_supply.h

@@ -274,7 +274,6 @@ struct power_supply_desc {
 	int (*property_is_writeable)(struct power_supply *psy,
 				     enum power_supply_property psp);
 	void (*external_power_changed)(struct power_supply *psy);
-	void (*set_charged)(struct power_supply *psy);
 
 	/*
 	 * Set if thermal zone should not be created for this power supply.