TI-SCI message protocol provides support for management of various
hardware entities within the SoC.

In general, we expect to function at a device level of abstraction,
however, for proper operation of hardware blocks, many clocks directly
supplying the hardware block needs to be queried or configured.

Introduce support for the set of TI-SCI message protocol support that
provide us with this capability.

Signed-off-by: Andrew F. Davis <afd@ti.com>
Reviewed-by: Andreas Dannenberg <dannenberg@ti.com>