iproute2: misc/ss.c - fix run_ssfilter af_packet when protocol == 0

iproute2: misc/ss.c - fix run_ssfilter af_packet when protocol == 0

s->local.data is a pointer to a field of a non-NULL struct, and hence
cannot be NULL, thus comparing it to 0 is always false, and thus the
return is always false.

Presumably this was meant to be a check whether s->local.data[0] (which
I believe stores af_packet protocol) is 0, ie. ANY.

Change-Id: Ia232f5b06ce081e3b2fb6338f1a709cd94e03ae5
Fixes:
  ss.c:1018:37: error: comparison of array 's->local.data' equal to a null pointer is always false [-Werror,-Wtautological-pointer-compare]
    return s->lport == 0 && s->local.data == 0;
                            ~~~~~~~~~^~~~    ~
  1 error generated.