hikey: flush led for exception signals
hikey: flush led for exception signals

Signed-off-by: Haojian Zhuang <979139d45d262f0480136b0da512e0afa0fe79d3@linaro.org>

jforissier/arm-trusted-firmware,Leo-Yan/arm-trusted-firmware,vchong/arm-trusted-firmware,vchong/arm-trusted-firmware,jforissier/arm-trusted-firmware,96boards/arm-trusted-firmware,96boards/arm-trusted-firmware,Leo-Yan/arm-trusted-firmware