mfd: max8925: Remove the unused function irq_to_max8925()

The function irq_to_max8925() is defined in the max8925-core.c
file, but not called elsewhere, so remove this unused function.

  drivers/mfd/max8925-core.c:472:40: warning: unused function 'irq_to_max8925'.

Link: https://bugzilla.openanolis.cn/show_bug.cgi?id=3561Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: Lee Jones <lee@kernel.org>
Link: https://lore.kernel.org/r/20221227081805.54185-1-jiapeng.chong@linux.alibaba.com

drivers/mfd/max8925-core.c

@@ -469,12 +469,6 @@ static struct max8925_irq_data max8925_irqs[] = {
 	},
 };
 
-static inline struct max8925_irq_data *irq_to_max8925(struct max8925_chip *chip,
-						      int irq)
-{
-	return &max8925_irqs[irq - chip->irq_base];
-}
-
 static irqreturn_t max8925_irq(int irq, void *data)
 {
 	struct max8925_chip *chip = data;