refactor(fvp): do not use RSS platform token and attestation key APIs

Since FVP does not support RSS, RSS APIs used to provide the hardcoded
platform token and attestation key. However, that seems to be causing
un-necessary mandating of some PSA crypto definitions, that doesn't
seem appropriate.
Hence to retrieve platform token and realm attestation key, these
RSS APIs calls have been replaced with hardcoded information.

Change-Id: I5fd091025e3444a698b9d387763ce20db6b13ae1
Signed-off-by: Manish V Badarkhe <Manish.Badarkhe@arm.com>
4 files changed