parser_bison: turn redundant ip option type field match into boolean

parser_bison: turn redundant ip option type field match into boolean

The ip option expression allows for non-sense matching like:

	ip option lsrr type 1

because 'lsrr' already provides the type field, this never results in a
matching.

Turn this expression into:

	ip option lsrr exists

And update documentation to hide this redundant type field.

Fixes: 226a0e072d5c ("exthdr: add support for matching IPv4 options")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>