staging: wilc1000: fix line over 80 char in wilc_wlan_handle_rxq()

Refactor wilc_wlan_handle_rxq() to fix line over 80 character issue
found by checkpatch.pl script. Added a new function to split
'wilc_wlan_handle_rxq' function code.

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