drivers: gpio: add driver for Microchip PIC32 GPIO controller.

In PIC32 GPIO controller is part of PIC32 pin controller.
PIC32 has ten independently programmable ports and each with multiple pins.
Each of these pins can be configured and used as GPIO, provided they
are not in use for other peripherals.

Signed-off-by: Purna Chandra Mandal <purna.mandal@microchip.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index e60e9fd..845dc72 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -83,4 +83,11 @@
 	help
 	  Say yes here to support Vybrid vf610 GPIOs.
 
+config PIC32_GPIO
+	bool "Microchip PIC32 GPIO driver"
+	depends on DM_GPIO && MACH_PIC32
+	default y
+	help
+	  Say yes here to support Microchip PIC32 GPIOs.
+
 endmenu