RDMA/hfi1: Fix build error with debugfs disabled

A recent patch set to rework the usage of debugfs and to add fault
injection capabilities via debugfs files to the hfi1 driver introduced a
build error that only shows up when debugfs is fully disabled.  The
patchset mistakenly defines some empty stub functions in two different
headers when debugfs is disabled.  Remove the set that shouldn't have
been there to resolve the issue.

Fixes: a74d5307 ("IB/hfi1: Rework fault injection machinery")
Signed-off-by: Doug Ledford <dledford@redhat.com>