llc: Use normal etherdevice.h tests

Convert the llc_<foo> static inlines to the
equivalents from etherdevice.h and remove
the llc_<foo> static inline functions.

llc_mac_null -> is_zero_ether_addr
llc_mac_multicast -> is_multicast_ether_addr
llc_mac_match -> ether_addr_equal

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>