extcon: axp288: Remove unused extcon_nb struct member

Remove the unused extcon_nb struct member.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>

drivers/extcon/extcon-axp288.c

@@ -107,7 +107,6 @@ struct axp288_extcon_info {
 	struct gpio_desc *gpio_mux_cntl;
 	int irq[EXTCON_IRQ_END];
 	struct extcon_dev *edev;
-	struct notifier_block extcon_nb;
 	unsigned int previous_cable;
 };