staging: wilc1000: use kmemdup instead of kmalloc and memcpy

Kmalloc followed by memcpy can be replaced by kmemdup.

Signed-off-by: HariPrasath Elango <hariprasath.elango@gmail.com>
Reviewed-by: Ajay Singh <ajay.kathat@microchip.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>