zebra: Add encap type when building packet for FPM

Currently in the single nexthop case w/ evpn sending
down via the FPM the encap type is not being set
for the nexthop.

This looks like the result of some code reorg for the
nexthop happened but the fpm failed to be accounted for.
Let's just move the encap type encoding to where it
will happen.

Signed-off-by: Donald Sharp <sharpd@nvidia.com>
(cherry picked from commit 4ac659f)

zebra/rt_netlink.c

@@ -2235,19 +2235,21 @@ ssize_t netlink_route_multipath_msg_encode(int cmd,
 					    p, routedesc, bytelen, nexthop,
 					    &req->n, &req->r, datalen, cmd))
 					return 0;
+
+				/*
+				 * Add encapsulation information when
+				 * installing via FPM.
+				 */
+				if (fpm) {
+					if (!netlink_route_nexthop_encap(&req->n,
+									 datalen,
+									 nexthop))
+						return 0;
+				}
+
 				nexthop_num++;
 				break;
 			}
-
-			/*
-			 * Add encapsulation information when installing via
-			 * FPM.
-			 */
-			if (fpm) {
-				if (!netlink_route_nexthop_encap(
-					    &req->n, datalen, nexthop))
-					return 0;
-			}
 		}
 
 		if (setsrc) {