staging: wilc1000: simplify msgqueue code

The driver contains an abstraction for message queues, with
optional unused features, while the driver requires the main
feature.

This makes the msgqueue code unconditional as it's required
but removes the unused parts.

A later cleanup should remove the entire msgqueue code
and replace it with some normal kernel API.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>