RDMA/usnic: Fix misuse of sysfs_emit_at

In commit e28bf1f03b ("RDMA: Convert various random sprintf sysfs _show
uses to sysfs_emit") I mistakenly used len = sysfs_emit_at to overwrite
the last trailing space of potentially multiple entry output.

Instead use a more common style by removing the trailing space from the
output formats and adding a prefixing space to the contination formats and
converting the final terminating output newline from the defective
	len = sysfs_emit_at(buf, len, "\n");
to the now appropriate and typical
	len += sysfs_emit_at(buf, len, "\n");

Fixes: e28bf1f03b ("RDMA: Convert various random sprintf sysfs _show uses to sysfs_emit")
Link: https://lore.kernel.org/r/5eb794b9c9bca0494d94b2b209f1627fa4e7b555.camel@perches.com
Reported-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/hw/usnic/usnic_ib_sysfs.c

@@ -214,7 +214,7 @@ static ssize_t summary_show(struct usnic_ib_qp_grp *qp_grp, char *buf)
 	struct usnic_vnic_res *vnic_res;
 	int len;
 
-	len = sysfs_emit(buf, "QPN: %d State: (%s) PID: %u VF Idx: %hu ",
+	len = sysfs_emit(buf, "QPN: %d State: (%s) PID: %u VF Idx: %hu",
 			 qp_grp->ibqp.qp_num,
 			 usnic_ib_qp_grp_state_to_string(qp_grp->state),
 			 qp_grp->owner_pid,
@@ -224,14 +224,13 @@ static ssize_t summary_show(struct usnic_ib_qp_grp *qp_grp, char *buf)
 		res_chunk = qp_grp->res_chunk_list[i];
 		for (j = 0; j < res_chunk->cnt; j++) {
 			vnic_res = res_chunk->res[j];
-			len += sysfs_emit_at(
-				buf, len, "%s[%d] ",
+			len += sysfs_emit_at(buf, len, " %s[%d]",
 				usnic_vnic_res_type_to_str(vnic_res->type),
 				vnic_res->vnic_idx);
 		}
 	}
 
-	len = sysfs_emit_at(buf, len, "\n");
+	len += sysfs_emit_at(buf, len, "\n");
 
 	return len;
 }