kernel.h: remove unused NIPQUAD and NIPQUAD_FMT

There are no more uses of NIPQUAD or NIPQUAD_FMT.  Remove the definitions.

Signed-off-by: Joe Perches <joe@perches.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>