[arm64] Enable SCMI framework

The SCMI specification provides a standardized interface for power, performance and resource management on a SoC.
The low-level management actions are performed by a system controller that directly controls the SoC hardware or platform.
The system controller provides SCMI interfaces to its clients.
A typical example of an SCMI client is an Operating System kernel.

Enable the needed modules so that Debian can be an SCMI client.
Make the core modules (from firmware/arm_scmi) built-in as well as modules related to pinctrl and power (may be needed in early boot), but enable the rest of the modules as loadable module.

Link: https://developer.arm.com/documentation/102886/001/
Link: https://developer.arm.com/documentation/den0056/latest/