staging: wilc1000: message_queue: Move code to host interface

Move the contents of wilc_msgqueue.c and wilc_msgqueue.h into
host_interface.c, remove 'wilc_msgqueue.c' and 'wilc_msgqueue.h'.
This is done so as to restructure the implementation of the kthread
'hostIFthread' using a work queue.

Signed-off-by: Binoy Jayan <binoy.jayan@linaro.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>