installer/hikey960: Label bl31/lpm3/nvme images as hisi specific

To make it more clear in the future when we're using UEFI,
label the hisi bootloader components as such so one can
easily descern which are provided blobs vs binaries built
from source.

Change-Id: I0b24777bfea9212538a5ee514687b17f68115428
Signed-off-by: John Stultz <john.stultz@linaro.org>
4 files changed