hikey: init voltage setting
hikey: init voltage setting

With mcu firmware mcuimage_b0211.bin, init the voltage level and
limitation for it.

Signed-off-by: Leo Yan <a38ad1fbd0b3373e0c012f4d28e16dbce652d487@linaro.org>

96boards/arm-trusted-firmware,96boards/arm-trusted-firmware,vchong/arm-trusted-firmware,vchong/arm-trusted-firmware