netfilter: Reduce switch/case indent

Make the case labels the same indent as the switch.

git diff -w shows miscellaneous 80 column wrapping,
comment reflowing and a comment for a useless gcc
warning for an otherwise unused default: case.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>