staging/wlan-ng: compare using ether_addr_equal_unaligned

Replaced generic memcmp() with dedicated ether_addr_equal_unaligned()
call. I did not find any clue of u16 alignment for both addresses.

Signed-off-by: Denis Pithon <denis.pithon@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>