ntb: transport shouldn't disable link due to bogus values in SPADs

ntb: transport shouldn't disable link due to bogus values in SPADs

It seems that under certain scenarios the SPAD can have bogus values caused
by an agent (i.e. BIOS or other software) that is not the kernel driver, and
that causes memory window setup failure. This should not cause the link to
be disabled because if we do that, the driver will never recover again. We
have verified in testing that this issue happens and prevents proper link
recovery.

Signed-off-by: Dave Jiang <[email protected]>
Acked-by: Allen Hubbe <[email protected]>
Signed-off-by: Jon Mason <[email protected]>
Fixes: 84f766855f61 ("ntb: stop link work when we do not have memory")