SELFOUR-519: remove more duplication in hardware.c

include/plat/allwinnerA20/plat/machine/hardware.h

include/plat/am335x/plat/machine/hardware.h

include/plat/apq8064/plat/machine/hardware.h

include/plat/exynos4/plat/machine/hardware.h

include/plat/exynos5/plat/machine/hardware.h

include/plat/hikey/plat/machine/hardware.h

include/plat/imx31/plat/machine/hardware.h

include/plat/imx6/plat/machine/hardware.h

include/plat/imx7/plat/machine/hardware.h

include/plat/omap3/plat/machine/hardware.h

include/plat/tk1/plat/machine/hardware.h

include/plat/zynq7000/plat/machine/hardware.h

src/arch/arm/32/machine/hardware.c

src/plat/allwinnerA20/machine/hardware.c

src/plat/am335x/machine/hardware.c

src/plat/apq8064/machine/hardware.c

src/plat/exynos4/machine/hardware.c

src/plat/exynos5/machine/hardware.c

src/plat/hikey/machine/hardware.c

src/plat/imx31/machine/hardware.c