Revert "Hikey960: Change to use recommended power state id format"

Revert "Hikey960: Change to use recommended power state id format"

This reverts commit fdae60b6ba27c216fd86d13b7432a1ff4f57dd84.

The commit fdae60b6ba27c216fd86d13b7432a1ff4f57dd84 changed the
parameter encoding for the hikey960.  However that implies a DT change
in the kernel side.  After submitting the DT change for upstreaming,
the backward compatibility issue and the interface change raise some
concerns from the Linux community about the issues related to kernel <->
ATF alignment.  There is no way to detect a mis-alignment of those
without a deep knowledge of the ATF and the kernel.  Furthermore, the
failing calls to PSCI in the idle path (because of bad parameters), will
lead to busy looping, implying: thermal issues and extra energy
consumption.

In regard of the Linux community concerns, the potential issues when the
ATF and the kernel are not aligned, it is preferable to revert the
commit.

Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Haojian Zhuang <haojian.zhuang@linaro.org>
Cc: Kevin Wang <jean.wangtao@linaro.org>
Co-authored-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Leo Yan <leo.yan@linaro.org>