netfilter: limit, hashlimit: avoid duplicated inline

credit_cap can be set to credit, which avoids inlining user2credits
twice. Also, remove inline keyword and let compiler decide.

old:
    684     192       0     876     36c net/netfilter/xt_limit.o
   4927     344      32    5303    14b7 net/netfilter/xt_hashlimit.o
now:
    668     192       0     860     35c net/netfilter/xt_limit.o
   4793     344      32    5169    1431 net/netfilter/xt_hashlimit.o

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>