staging: wilc1000: added 'work_comp' completion as part of host_if_msg

Added 'work_comp' completion in 'host_if_msg'. It allows handling the
sync call to wait for sepecific completion event.
The commands can be run in sync way waiting for their specific
completion event.
Added is_sync flag in wilc_create_work_queue() to handle the sync call to
host interface.

After adding completion as part of host_if_msg now
below completion are not required
 comp_test_key_block;
 comp_test_disconn_block
 comp_get_rssi
 comp_inactive_time
 hif_wait_response

Modified wilc_get_statistics() API to handle get statistic in sync &
async way.

Signed-off-by: Ajay Singh <ajay.kathat@microchip.com>
Reviewed-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>