lldp: Fix DPDK build.

lldp: Fix DPDK build.

Fixes following dp-packet access. Removes netinet/if_ether.h
include due to duplicate definition of ether_addr.

------
In file included from /usr/include/netinet/if_ether.h:60:0,
                 from lib/lldp/lldpd.h:23,
                 from lib/ovs-lldp.h:26,
                 from lib/ovs-lldp.c:30:
/usr/include/net/ethernet.h: At top level:
/usr/include/net/ethernet.h:32:8: error: redefinition of 'struct
ether_addr'
 struct ether_addr
        ^
In file included from
../dpdk/dpdk/x86_64-native-linuxapp-gcc/include/rte_ethdev.h:179:0,
                 from lib/netdev-dpdk.h:18,
                 from lib/dp-packet.h:25,
                 from lib/ovs-lldp.h:23,
                 from lib/ovs-lldp.c:30:
../dpdk/dpdk/x86_64-native-linuxapp-gcc/include/rte_ether.h:83:8: note:
originally defined here
 struct ether_addr {
        ^
lib/ovs-lldp.c: In function 'lldp_process_packet':
lib/ovs-lldp.c:676:30: error: 'const struct dp_packet' has no member
named 'data_'
                    (char *) p->data_, p->size_);
                              ^
lib/ovs-lldp.c:676:40: error: 'const struct dp_packet' has no member
named 'size_'
                    (char *) p->data_, p->size_);
------

Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Acked-by: Daniele Di Proietto <diproiettod@vmware.com>
Acked-by: Ben Pfaff <blp@nicira.com>