crypto: ccp - Allow SEV firmware to be chosen based on Family and Model

During PSP initialization, there is an attempt to update the SEV firmware
by looking in /lib/firmware/amd/. Currently, sev.fw is the expected name
of the firmware blob.

This patch will allow for firmware filenames based on the family and
model of the processor.

Model specific firmware files are given highest priority. Followed by
firmware for a subset of models. Lastly, failing the previous two options,
fallback to looking for sev.fw.

Signed-off-by: Janakarajan Natarajan <Janakarajan.Natarajan@amd.com>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Acked-by: Gary R Hook <gary.hook@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>