Depend on DPE in Mailbox API

[sree-revoori1]

We should take the max sizes for the InvokeDpeResp and InvokeDpeReq structs from DPE command and response structs instead of using magic numbers. Same goes for CertifyKeyExtendedReq and CertifyKeyExtendedResp. Adding this dependency will cause the ROM binary to change, so we should add it optionally behind a runtime CFG flag.