net/ena: proxy AQ calls to primary process

net/ena: proxy AQ calls to primary process

Due to how the ena_com compatibility layer is written, all AQ commands
triggering functions use stack to save results of AQ and then copy them
to user given function.
Therefore to keep the compatibility layer common, introduce ENA_PROXY
macro. It either calls the wrapped function directly (in primary
process) or proxies it to the primary via DPDK IPC mechanism. Since all
proxied calls are taken under a lock share the result data through
shared memory (in struct ena_adapter) to work around 256B IPC parameter
size limit.

New proxy calls can be added by
1. Adding a new message type at the end of enum ena_mp_req
2. Adding new message arguments to the struct ena_mp_body if needed
3. Defining proxy request descriptor with ENA_PROXY_DESC. Its arguments
   include handlers for request preparation and response processing.
   Any of those may be empty (aside of marking arguments as used).
4. Adding request handling logic to ena_mp_primary_handle()
5. Replacing proxied function calls with ENA_PROXY(adapter, <func>, ...)

Signed-off-by: Stanislaw Kardach <kda@semihalf.com>
Reviewed-by: Michal Krawczyk <mk@semihalf.com>
Reviewed-by: Dawid Gorecki <dgr@semihalf.com>
Reviewed-by: Shai Brandes <shaibran@amazon.com>