datatype: do not assert when value exceeds expected width

datatype: do not assert when value exceeds expected width

Inputs:
ip protocol . th dport { tcp / 22,  }'
or
th dport . ip protocol { tcp / 22,  }'

are not rejected at this time. 'list ruleset' yields:
 ip protocol & nft: src/gmputil.c:77: mpz_get_uint8: Assertion `cnt <= 1' failed.
or
 th dport & nft: src/gmputil.c:87: mpz_get_be16: Assertion `cnt <= 1' failed.

While this should be caught at input too, the print path should be more
robust, e.g. when there are direct nfnetlink users.

After this patch, the print functions fall back to
'integer_type_print' which can handle large numbers too.

Note that the output printed this way cannot be read back by nft;
it will dump something like:

  tcp dport & 18446739675663040512 . ip protocol 0 . 0

but thats better than assert().

v2: same problem exists for service too.

Signed-off-by: Florian Westphal <fw@strlen.de>