IB/hfi1: Check for error on call to alloc_rsm_map_table

The call to alloc_rsm_map_table does not check if the kmalloc fails.
Check for a NULL on alloc, and bail if it fails.

Fixes: 372cc85a ("IB/hfi1: Extract RSM map table init from QOS")
Link: https://lore.kernel.org/r/20190715164521.74174.27047.stgit@awfm-01.aw.intel.com


Cc: <stable@vger.kernel.org>
Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: John Fleck <john.fleck@intel.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>