netfilter: Factor out the hook list selection from nf_register_hook
netfilter: Factor out the hook list selection from nf_register_hook

- Add a new function find_nf_hook_list to select the nf_hook_list

- Fail nf_register_hook when asked for a per netdevice hook list when
  support for per netdevice hook lists is not built into the kernel.

- Move the hook list head selection outside of nf_hook_mutex as
  nothing in the selection requires the hook list, and error handling
  is simpler if a mutex is not held.

Signed-off-by: "Eric W. Biederman" <8a741aa8cbd77ebc4a56ddb528ce9fd15d42f034@xmission.com>
Signed-off-by: Pablo Neira Ayuso <707d14912bb250caf67dfe0ea4035681fbfc4f56@netfilter.org>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs