PM / devfreq: rk3399_dmc: Drop excess timing properties

All of these properties are initialized by ARM Trusted Firmware, and
have been since the early days of this chip. It's redundant (and
possibly wrong) to do this here now. What's more, there seems to be some
confusion about the units and some of the definitions of this timing
struct: the DT docs say MHz for many of these, but downstream users were
in Hz (and therefore, the ATF interface was Hz). Also, the in-driver
usage for some of these (e.g., for comparing to target frequency) were
in Hz too. So doubly wrong.

We can avoid thinking about who got the right units by dropping the
unnecessary code and properties. They are marked deprecated in the
binding schema.

Signed-off-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>