gpu: nova-core: Hopper/Blackwell: add FSP send/receive messaging

gpu: nova-core: Hopper/Blackwell: add FSP send/receive messaging

FSP exchanges are request/response: the driver sends an MCTP/NVDM
message and must match the reply against the request before acting on
it. Add the synchronous send-and-wait path that validates the response
transport and message headers and confirms the reply corresponds to the
request that was sent.

Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Eliot Courtney <ecourtney@nvidia.com>
Link: https://patch.msgid.link/20260603-b4-blackwell-v13-4-d9f3a06939e0@nvidia.com
[acourbot: make `MessageToFsp` private.]
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>