Silicon/SynQuacer/PlatformDxe: add ACPI device node for OP-TEE if present

In order to allow the OS to discover the presence of OP-TEE also when
booting via ACPI, expose a PRP0001 ACPI device node in this case with
OP-TEE's DT compatible string attached.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>