ArmPkg: Add FID definitions for Arm TRNG

Bugzilla: 3668 (https://bugzilla.tianocore.org/show_bug.cgi?id=3668)

The Arm True Random Number Generator Firmware, Interface 1.0,
Platform Design Document
(https://developer.arm.com/documentation/den0098/latest/

)
defines an interface between an Operating System (OS) executing
at EL1 and Firmware (FW) exposing a conditioned entropy source
that is provided by a TRNG back end.

New function IDs have been defined by the specification for
accessing the TRNG services. Therefore, add these definitions
to the Arm standard SMC header.

Signed-off-by: Pierre Gondois <pierre.gondois@arm.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>