U5SeriesPkg/RamFvbServicesRuntimeDxe: Add PcdProtocol as dependency

This will ensure that it is dispatched properly by the DXE dispatcher,
which means it doesn't have to go in the APRIORI section.

Signed-off-by: Daniel Schaefer <daniel.schaefer@hpe.com>

Cc: Abner Chang <abner.chang@hpe.com>
Cc: Leif Lindholm <leif@nuviainc.com>
Cc: Gilbert Chen <gilbert.chen@hpe.com>
Cc: Ard Biesheuvel <ard.biesheuvel@arm.com>