net: udp: fix alignment problem in udp4_seq_show()

$ cat /pro/net/udp

before:

  sl  local_address rem_address   st tx_queue rx_queue tr tm->when
26050: 0100007F:0035 00000000:0000 07 00000000:00000000 00:00000000
26320: 0100007F:0143 00000000:0000 07 00000000:00000000 00:00000000
27135: 00000000:8472 00000000:0000 07 00000000:00000000 00:00000000

after:

   sl  local_address rem_address   st tx_queue rx_queue tr tm->when
26050: 0100007F:0035 00000000:0000 07 00000000:00000000 00:00000000
26320: 0100007F:0143 00000000:0000 07 00000000:00000000 00:00000000
27135: 00000000:8472 00000000:0000 07 00000000:00000000 00:00000000
Signed-off-by: yangxingwu <xingwu.yang@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>