gpio/ep93xx: Add missing EP93XX_GPIO_PHYS_BASE define

The patch to convert of the ep93xx gpio driver to a platform_driver is
missing the define for the memory resource that is passed to the driver.

This is needed to prevent a build error.
Signed-off-by: NH Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>

arch/arm/mach-ep93xx/include/mach/ep93xx-regs.h

@@ -98,6 +98,7 @@
 
 #define EP93XX_SECURITY_BASE		EP93XX_APB_IOMEM(0x00030000)
 
+#define EP93XX_GPIO_PHYS_BASE		EP93XX_APB_PHYS(0x00040000)
 #define EP93XX_GPIO_BASE		EP93XX_APB_IOMEM(0x00040000)
 #define EP93XX_GPIO_REG(x)		(EP93XX_GPIO_BASE + (x))
 #define EP93XX_GPIO_F_INT_STATUS	EP93XX_GPIO_REG(0x5c)