RDMA/ocrdma: Convert kernel VA to PA for mmap in user

In some platforms, when iommu is enabled, the bus address returned by
dma_alloc_coherent is different than the physical address.  ocrdma
should use physical address for mmap-ing the queue memory for the
applications.

This patch adds the use of virt_to_phys() at all such places where
kernel buffer is mapped to user process context.

Signed-off-by: Devesh Sharma <devesh.sharma@emulex.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>