As it's not always obvious what PSP bootloader or TEE version are
present in OEM systems, add the ability to get this information from
sysfs for supported platforms.

Acked-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>