iwlagn: move reclaim related functions

Now that the reclaim flow has been moved to the transport layer, a lot of
functions can be made static or don't need to be exported outside the transport
layer.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>