gpu: nova-core: gsp: add reply/no-reply info to `CommandToGsp`

gpu: nova-core: gsp: add reply/no-reply info to `CommandToGsp`

Add type infrastructure to know what reply is expected from each
`CommandToGsp`. Uses a marker type `NoReply` which does not implement
`MessageFromGsp` to mark commands which don't expect a response.

Update `send_command` to wait for a reply and add `send_command_no_wait`
which sends a command that has no reply, without blocking.

This prepares for adding locking to the queue.

Tested-by: Zhi Wang <zhiw@nvidia.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Eliot Courtney <ecourtney@nvidia.com>
Link: https://patch.msgid.link/20260318-cmdq-locking-v5-3-18b37e3f9069@nvidia.com
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>