RDMA/hfi1: Prevent memory leak in sdma_init

In sdma_init if rhashtable_init fails the allocated memory for
tmp_sdma_rht should be released.

Fixes: 5a52a7acf7e2 ("IB/hfi1: NULL pointer dereference when freeing rhashtable")
Link: https://lore.kernel.org/r/20190925144543.10141-1-navid.emamdoost@gmail.com
Signed-off-by: Navid Emamdoost <navid.emamdoost@gmail.com>
Acked-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
