arm: mach-pxa: Decrement the power supply's device reference counter

Use power_supply_put() to decrement the power supply's device reference
counter.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Reviewed-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Reviewed-by: Sebastian Reichel <sre@kernel.org>
Acked-by: Robert Jarzmik <robert.jarzmik@free.fr>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Sebastian Reichel <sre@kernel.org>