DPE: Add custom argument cert_id to DeriveContext

Cert_id is custom argument passed by the client to DeriveContext
to assign the context to specific certificate. For now only
support the parameter as mandatory input.

Signed-off-by: Maulik Patel <maulik.patel@arm.com>
Change-Id: Ib8c00cbab8fd0ad5b49012d854ae3fc6077409b9
10 files changed