lpc32xx: add GPIO support

This driver only supports Driver Model, not legacy model.

Signed-off-by: Albert ARIBAUD (3ADEV) <albert.aribaud@3adev.fr>
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index fe9a3b2..85f71c5 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -41,3 +41,4 @@
 obj-$(CONFIG_TCA642X)		+= tca642x.o
 oby-$(CONFIG_SX151X)		+= sx151x.o
 obj-$(CONFIG_SUNXI_GPIO)	+= sunxi_gpio.o
+obj-$(CONFIG_LPC32XX_GPIO)	+= lpc32xx_gpio.o