NTB: Fix issue where we may be accessing NULL ptr
NTB: Fix issue where we may be accessing NULL ptr

smatch detected an issue in the function ntb_transport_max_size() where
we could be dereferencing a dma channel pointer when it is NULL.

Reported-by: Dan Carpenter <ff341aa343d564f9e53e9dcb6996be8c04859a66@oracle.com>
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