[ARM] 5574/1: ep93xx: gpio.c: fix header includes and __iomem pointers

Fix ep93xx gpio.c header includes and __iomem pointers.

  1. <linux/gpio.h> should be included instead of <asm/gpio.h>
  2. <mach/hardware.h> should be included instead of <mach/ep93xx-regs.h>
  3. data_reg and data_dir_reg in struct ep93xx_gpio_chip should be
     void __iomem pointers not unsigned int

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Acked-by: Ryan Mallon <ryan@bluewatersys.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>