Compile fixes for kernel >= 3.2

Fixes compile error:
 error: implicit declaration of function ‘try_then_request_module’

Signed-off-by: Jesper Dangaard Brouer <netoptimizer@brouer.com>
Compile compat for kernel >= v3.8.0

Syntax changed for some macros in kernel 3.8, used in this module:
 hlist_for_each_entry_safe()
 hlist_for_each_entry_rcu()

This were caused by
 commit b67bfe0d42 (hlist: drop the node parameter from iterators)

Workaround this with some defines.

Signed-off-by: Jesper Dangaard Brouer <netoptimizer@brouer.com>