iwlwifi: mvm: clean up queue sync implementation

iwlwifi: mvm: clean up queue sync implementation

When we do queue sync, it's confusing that we have the structures
declared in the FW API header files that aren't really firmware,
and the union is also confusing - especially now in the code that
checks the size on the return.

So rework this: change the type of sync and whether to do it in a
synchronous fashion to arguments, and build the data structure in
the function, so we don't need the union.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20210331121101.f62833fd9893.I612d7ac1c655ec4880329360e15d207698c750bc@changeid
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>