gpio: mb86s7x: Remove superfluous test for ACPI companion

acpi_gpiochip_request_interrupts() will check for ACPI handle of
the GPIO chip parent device and bail out if there is none defined.
Thus, has_acpi_companion() is effectively repeating above and
is not needed in the individual driver.

Assigning ->to_irq() unconditionally doesn't change anything, except
an error code, but this we fix as well by propagating it from
platform_get_irq().
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200512182623.54990-2-andriy.shevchenko@linux.intel.comSigned-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpio-mb86s7x.c

@@ -145,7 +145,9 @@ static int mb86s70_gpio_to_irq(struct gpio_chip *gc, unsigned int offset)
 
 	for (index = 0;; index++) {
 		irq = platform_get_irq(to_platform_device(gc->parent), index);
-		if (irq <= 0)
+		if (irq < 0)
+			return irq;
+		if (irq == 0)
 			break;
 		if (irq_get_irq_data(irq)->hwirq == offset)
 			return irq;
@@ -184,15 +186,13 @@ static int mb86s70_gpio_probe(struct platform_device *pdev)
 	gchip->gc.free = mb86s70_gpio_free;
 	gchip->gc.get = mb86s70_gpio_get;
 	gchip->gc.set = mb86s70_gpio_set;
+	gchip->gc.to_irq = mb86s70_gpio_to_irq;
 	gchip->gc.label = dev_name(&pdev->dev);
 	gchip->gc.ngpio = 32;
 	gchip->gc.owner = THIS_MODULE;
 	gchip->gc.parent = &pdev->dev;
 	gchip->gc.base = -1;
 
-	if (has_acpi_companion(&pdev->dev))
-		gchip->gc.to_irq = mb86s70_gpio_to_irq;
-
 	ret = gpiochip_add_data(&gchip->gc, gchip);
 	if (ret) {
 		dev_err(&pdev->dev, "couldn't register gpio driver\n");
@@ -200,8 +200,7 @@ static int mb86s70_gpio_probe(struct platform_device *pdev)
 		return ret;
 	}
 
-	if (has_acpi_companion(&pdev->dev))
-		acpi_gpiochip_request_interrupts(&gchip->gc);
+	acpi_gpiochip_request_interrupts(&gchip->gc);
 
 	return 0;
 }
@@ -210,8 +209,7 @@ static int mb86s70_gpio_remove(struct platform_device *pdev)
 {
 	struct mb86s70_gpio_chip *gchip = platform_get_drvdata(pdev);
 
-	if (has_acpi_companion(&pdev->dev))
-		acpi_gpiochip_free_interrupts(&gchip->gc);
+	acpi_gpiochip_free_interrupts(&gchip->gc);
 	gpiochip_remove(&gchip->gc);
 	clk_disable_unprepare(gchip->clk);