firmware/psci: Add definitions for PSCI v1.3 specification

The v1.3 PSCI spec (https://developer.arm.com/documentation/den0022

) adds
the SYSTEM_OFF2 function. Add definitions for it and its hibernation type
parameter.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Miguel Luis <miguel.luis@oracle.com>
Link: https://lore.kernel.org/r/20241019172459.2241939-2-dwmw2@infradead.org


Signed-off-by: Oliver Upton <oliver.upton@linux.dev>