ia64: ensure exception table search users include extable.h

ia64: ensure exception table search users include extable.h

We start with a delete of a duplicate prototype in asm/exception.h
that no longer needs to exist, as it duplicates content in extable.h
and since that header is so small, there is no point trying to
avoid using it.

Then we make sure anyone using search_exception_tables directly or
via the ia64_done_with_exception macro has included extable.h

In the process, we remove an include of moduleloader.h that was
apparently not really required; it would have been fetching in
module.h and hence the previous location of the exception search
function prototypes, but we need not rely on that anymore.

Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: linux-ia64@vger.kernel.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>