atmel_lcdfb: Eliminate unneeded #include <asm/arch/hardware.h>

atmel_lcdfb doesn't actually need anything from asm/arch/hardware.h. It
includes a file that does, asm/arch/gpio.h, but this file doesn't
include <asm/arch/hardware.h> like it's supposed to.

Add the missing include to asm/arch/gpio.h and remove the workaround
from the atmel_lcdfb driver. This makes the driver compile on avr32.

Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
Signed-off-by: Anatolij Gustschin <agust@denx.de>