NTB: Change WARN_ON_ONCE to pr_warn_once on unsafe
NTB: Change WARN_ON_ONCE to pr_warn_once on unsafe

The unsafe doorbell and scratchpad access should display reason when
WARN is called.  Otherwise we get a stack dump without any explanation.

Signed-off-by: Dave Jiang <7a72b0ecdf501e4593e842e1a61bf3d5b53699e6@intel.com>
Signed-off-by: Jon Mason <cac3dbc234078e69b21f0609d62c20cd232525f0@kudzu.us>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs