power_supply: 88pm860x_charger: Do not call free_irq() twice

My static checker detected double free_irq() in pm860x_charger_remove().
Unloading this module always causes a warning. This patch removes the
first redundant free_irq() call.

Signed-off-by: Takeshi Yoshimura <yos@sslab.ics.keio.ac.jp>
Signed-off-by: Sebastian Reichel <sre@kernel.org>