IB/rdmavt: Add support for ib_map_mr_sg

This implements the device specific function needed by the verbs
API function ib_map_mr_sg().

Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Jianxin Xiong <jianxin.xiong@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/sw/rdmavt/mr.h

@@ -82,6 +82,8 @@ int rvt_dereg_mr(struct ib_mr *ibmr);
 struct ib_mr *rvt_alloc_mr(struct ib_pd *pd,
 			   enum ib_mr_type mr_type,
 			   u32 max_num_sg);
+int rvt_map_mr_sg(struct ib_mr *ibmr, struct scatterlist *sg,
+		  int sg_nents, unsigned int *sg_offset);
 struct ib_fmr *rvt_alloc_fmr(struct ib_pd *pd, int mr_access_flags,
 			     struct ib_fmr_attr *fmr_attr);
 int rvt_map_phys_fmr(struct ib_fmr *ibfmr, u64 *page_list,