The code tests the dma address which legitimately can be 0.

The code should test the kernel logical address to avoid leaking eager
buffer allocations that happen to map to a dma address of 0.

Fixes: 60368186 ("IB/hfi1: Fix user-space buffers mapping with IOMMU enabled")
Link: https://lore.kernel.org/r/20211129191952.101968.17137.stgit@awfm-01.cornelisnetworks.comSigned-off-by: NMike Marciniszyn <mike.marciniszyn@cornelisnetworks.com>
Signed-off-by: NDennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>
Signed-off-by: NJason Gunthorpe <jgg@nvidia.com>