firmware: ti_sci: Add support for processor control

Texas Instrument's System Control Interface (TI-SCI) Message Protocol
is used in Texas Instrument's System on Chip (SoC) such as those
in K3 family AM654 SoC to communicate between various compute
processors with a central system controller entity.

The system controller provides various services including the control
of other compute processors within the SoC. Extend the TI-SCI protocol
support to add various TI-SCI commands to invoke services associated
with power and reset control, and boot vector management of the
various compute processors from the Linux kernel.

Signed-off-by: Suman Anna <s-anna@ti.com>
Signed-off-by: Tero Kristo <t-kristo@ti.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>