net: pktgen: fix code style (WARNING: quoted string split across lines)

net: pktgen: fix code style (WARNING: quoted string split across lines)

Fix checkpatch code style warnings:

  WARNING: quoted string split across lines
  #480: FILE: net/core/pktgen.c:480:
  +       "Packet Generator for packet performance testing. "
  +       "Version: " VERSION "\n";

  WARNING: quoted string split across lines
  #632: FILE: net/core/pktgen.c:632:
  +                  "     udp_src_min: %d  udp_src_max: %d"
  +                  "  udp_dst_min: %d  udp_dst_max: %d\n",

Signed-off-by: Peter Seiderer <ps.report@gmx.net>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>