gemini: add Linux 4.4 support

Signed-off-by: Roman Yeryomin <roman@advem.lv>
[Jo-Philipp Wich: change commit title]
Signed-off-by: Jo-Philipp Wich <jo@mein.io>

target/linux/gemini/patches-4.4/050-gpio-to-irq.patch

@@ -0,0 +1,21 @@
+--- a/arch/arm/mach-gemini/gpio.c
++++ b/arch/arm/mach-gemini/gpio.c
+@@ -196,12 +196,18 @@ static int gemini_gpio_direction_output(
+ 	return 0;
+ }
+ 
++static int gemini_gpio_to_irq(struct gpio_chip *chip, unsigned gpio)
++{
++	return gpio + GPIO_IRQ_BASE;
++}
++
+ static struct gpio_chip gemini_gpio_chip = {
+ 	.label			= "Gemini",
+ 	.direction_input	= gemini_gpio_direction_input,
+ 	.get			= gemini_gpio_get,
+ 	.direction_output	= gemini_gpio_direction_output,
+ 	.set			= gemini_gpio_set,
++	.to_irq			= gemini_gpio_to_irq,
+ 	.base			= 0,
+ 	.ngpio			= GPIO_PORT_NUM * 32,
+ };