staging: mt7621-gpio: avoid check for NULL in 'to_mediatek_gpio' calls

Function 'to_mediatek_gpio' cannot return NULL, so this NULL
checkings are pointless.
Signed-off-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/mt7621-gpio/gpio-mt7621.c

@@ -115,9 +115,6 @@ mediatek_gpio_irq_unmask(struct irq_data *d)
 	unsigned long flags;
 	u32 rise, fall, high, low;
 
-	if (!rg)
-		return;
-
 	spin_lock_irqsave(&rg->lock, flags);
 	rise = mtk_gpio_r32(rg, GPIO_REG_REDGE);
 	fall = mtk_gpio_r32(rg, GPIO_REG_FEDGE);
@@ -139,9 +136,6 @@ mediatek_gpio_irq_mask(struct irq_data *d)
 	unsigned long flags;
 	u32 rise, fall, high, low;
 
-	if (!rg)
-		return;
-
 	spin_lock_irqsave(&rg->lock, flags);
 	rise = mtk_gpio_r32(rg, GPIO_REG_REDGE);
 	fall = mtk_gpio_r32(rg, GPIO_REG_FEDGE);
@@ -162,9 +156,6 @@ mediatek_gpio_irq_type(struct irq_data *d, unsigned int type)
 	int pin = d->hwirq;
 	u32 mask = BIT(pin);
 
-	if (!rg)
-		return -1;
-
 	if (type == IRQ_TYPE_PROBE) {
 		if ((rg->rising | rg->falling |
 		     rg->hlevel | rg->llevel) & mask)