staging: wilc1000: moved last_scanned_shadow & last_scanned_cnt to wilc_priv struct

Avoid use of static variables and moved the varibles as part of private
data. last_scanned_shadow & last_scanned_cnt variable is moved to
'wilc_priv' to maintain for each interface. After moving static
variable, clear_shadow_scan() doesn't require check 'op_ifcs'
count as now for each interface the againg timer is initiated.

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