sh: revert addition of page fault notifiers

Just at the time you added them on sh we're removing them from other
architectures. As there's no user yet this patch just removes them
completely. Once you actually have a kprobes patch it should follow
the direct call to kprobes_fault_handler model that powerpc, s390 and
sparc64 employ in 2.6.22-rc1 and that I'm updating other architectures
to.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>