staging: wilc1000: avoid 'NULL' pointer access in wilc_network_info_received()

Added 'NULL' check before accessing the allocated memory. Free up the
memory incase of failure to enqueue the command. Used kmemdup instead of
kmalloc & memcpy.

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>