IB/mad: Remove improper use of BUG_ON

We recently added BUG_ON's which were inappropriate for a condition which
should never happen. Change these to be WARN_ON_ONCE as a debugging aid.

Fixes: 4cd7c9479aff ('IB/mad: Add support for additional MAD info to/from drivers')

Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

diff --cc drivers/infiniband/hw/ehca/ehca_sqp.c
Simple merge

diff --cc drivers/infiniband/hw/ipath/ipath_mad.c
Simple merge

diff --cc drivers/infiniband/hw/mlx4/mad.c
Simple merge

diff --cc drivers/infiniband/hw/mlx5/mad.c
Simple merge

diff --cc drivers/infiniband/hw/mthca/mthca_mad.c
Simple merge

diff --cc drivers/infiniband/hw/ocrdma/ocrdma_ah.c
Simple merge

diff --cc drivers/infiniband/hw/qib/qib_mad.c
Simple merge