Since all the layers need to print debug message, the debug macro cannot suppose
that they will be given iwl_priv as a parameter and then dereference it.
Use iwl_shared instead.

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>