bpf: do not use reciprocal divide

bpf: do not use reciprocal divide

At first Jakub Zawadzki noticed that some divisions by reciprocal_divide
were not correct. (off by one in some cases)
http://www.wireshark.org/~darkjames/reciprocal-buggy.c

He could also show this with BPF:
http://www.wireshark.org/~darkjames/set-and-dump-filter-k-bug.c

The reciprocal divide in linux kernel is not generic enough,
lets remove its use in BPF, as it is not worth the pain with
current cpus.

Signed-off-by: Eric Dumazet <[email protected]>
Reported-by: Jakub Zawadzki <[email protected]>
Cc: Mircea Gherzan <[email protected]>
Cc: Daniel Borkmann <[email protected]>
Cc: Hannes Frederic Sowa <[email protected]>
Cc: Matt Evans <[email protected]>
Cc: Martin Schwidefsky <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: David S. Miller <[email protected]>
Signed-off-by: David S. Miller <[email protected]>