unicore32 io: redefine __REG(x) and re-use readl/writel funcs

arch/unicore32/include/asm/gpio.h

arch/unicore32/include/mach/dma.h

arch/unicore32/include/mach/hardware.h

arch/unicore32/kernel/clock.c

arch/unicore32/kernel/dma.c

arch/unicore32/kernel/gpio.c

arch/unicore32/kernel/irq.c

arch/unicore32/kernel/pci.c

arch/unicore32/kernel/process.c

arch/unicore32/kernel/puv3-core.c

arch/unicore32/kernel/rtc.c

arch/unicore32/kernel/time.c

drivers/input/serio/i8042-unicore32io.h