netfilter: ipset: remove inline from static functions in .c files.

The inline function-specifier should not be used for static functions
defined in .c files since it bloats the kernel.  Instead leave the
compiler to decide which functions to inline.

While a couple of the files affected (ip_set_*_gen.h) are technically
headers, they contain templates for generating the common parts of
particular set-types and so we treat them like .c files.

Signed-off-by: Jeremy Sowden <jeremy@azazel.net>
Acked-by: Jozsef Kadlecsik <kadlec@netfilter.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>