hikey960: Switch to using 5.4(gki) by default on hikey960

Now that we have prebuilt 5.4 binaries, lets use them by
default.

Signed-off-by: John Stultz <john.stultz@linaro.org>
Change-Id: I701f7a8d1bd07cef161209ad71c7af445f4b336d
1 file changed