bgpd, lib: adopt afi_t and safi_t in several places

* bgpd/bgp_attr.c, bgpd/bgp_open.h, bgpd/bgp_route.c, lib/prefix.c,
  lib/prefix.h: Various integer types were being used where, if we
  had strict type checking, afi_t and safi_t would be required.

Signed-off-by: G.Balaji <balajig81@gmail.com>
(cherry picked from commit c8af35ffa2dc79ff7d7ff00b1b61f1f50a100ab6)
diff --git a/bgpd/bgp_route.c b/bgpd/bgp_route.c
index a92ca4e..2391f74 100644
--- a/bgpd/bgp_route.c
+++ b/bgpd/bgp_route.c
@@ -3518,8 +3518,8 @@
 }
 
 static void
-bgp_static_update_vpnv4 (struct bgp *bgp, struct prefix *p, u_int16_t afi,
-			 u_char safi, struct prefix_rd *prd, u_char *tag)
+bgp_static_update_vpnv4 (struct bgp *bgp, struct prefix *p, afi_t afi,
+			 safi_t safi, struct prefix_rd *prd, u_char *tag)
 {
   struct bgp_node *rn;
   struct bgp_info *new;
@@ -3599,8 +3599,8 @@
 }
 
 static void
-bgp_static_withdraw_vpnv4 (struct bgp *bgp, struct prefix *p, u_int16_t afi,
-			   u_char safi, struct prefix_rd *prd, u_char *tag)
+bgp_static_withdraw_vpnv4 (struct bgp *bgp, struct prefix *p, afi_t afi,
+			   safi_t safi, struct prefix_rd *prd, u_char *tag)
 {
   struct bgp_node *rn;
   struct bgp_info *ri;
@@ -3653,7 +3653,7 @@
    route should be installed as valid.  */
 static int
 bgp_static_set (struct vty *vty, struct bgp *bgp, const char *ip_str, 
-                u_int16_t afi, u_char safi, const char *rmap, int backdoor,
+                afi_t afi, safi_t safi, const char *rmap, int backdoor,
                 u_char ttl)
 {
   int ret;
@@ -3798,7 +3798,7 @@
 /* Configure static BGP network. */
 static int
 bgp_static_unset (struct vty *vty, struct bgp *bgp, const char *ip_str,
-		  u_int16_t afi, u_char safi)
+		  afi_t afi, safi_t safi)
 {
   int ret;
   struct prefix p;
@@ -7622,7 +7622,7 @@
 
 static int
 bgp_show_community (struct vty *vty, int argc, const char **argv, int exact,
-                    u_int16_t afi, u_char safi)
+                    afi_t afi, safi_t safi)
 {
   struct community *com;
   struct buffer *b;
@@ -8622,7 +8622,7 @@
 
 static int
 bgp_show_community_list (struct vty *vty, const char *com, int exact,
-			 u_int16_t afi, u_char safi)
+			 afi_t afi, safi_t safi)
 {
   struct community_list *list;