net: ip_sockglue.c add static, annotate ports' endianness

Fixes sparse warnings:
net/ipv4/ip_sockglue.c:146:15: warning: incorrect type in assignment (different base types)
net/ipv4/ip_sockglue.c:146:15:    expected restricted __be16 [assigned] [usertype] sin_port
net/ipv4/ip_sockglue.c:146:15:    got unsigned short [unsigned] [short] [usertype] <noident>
net/ipv4/ip_sockglue.c:130:6: warning: symbol 'ip_cmsg_recv_dstaddr' was not declared. Should it be static?

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>