[NET]: Improve presentation of networking driver families.

Suggestion from Sam Ravnborg <sam@ravnborg.org>

It causes all driver families to be displayed aligned immediately under the
main network drivers heading (in menuconfig/xconfig/gconfig) instead of
not being subordinate to (i.e., not indented) the Network device support
heading at all.
The improved network driver families are:
  token ring, wireless, PCMCIA, WAN, ATM, and S390.

Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: David S. Miller <davem@davemloft.net>