firmware: ti_sci: Add support for firewall management

TI-SCI message protocol provides support for controlling the firewall
configurations available in SoC.

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

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