compat: make all modules depend on compat

compat: make all modules depend on compat

Sometimes, compat based drivers do not depend on
compat.ko because the base kernel is new enough.
This causes compat to not be loaded and makes it
harder to identify that the modules were based
on compat.

Re-define module_init() to make all modules that
were compiled against compat also require to be
linked against compat.ko.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luis R. Rodriguez <mcgrof@frijolero.org>