net: remove DST_NOGC flag

Now that all the components have been changed to release dst based on
refcnt only and not depend on dst gc anymore, we can remove the
temporary flag DST_NOGC.

Note that we also need to remove the DST_NOCACHE check in dst_release()
and dst_hold_safe() because now all the dst are released based on refcnt
and behaves as DST_NOCACHE.

Signed-off-by: Wei Wang <weiwan@google.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/dst.h b/include/net/dst.h
index 0c56d1f..1be82f6 100644
--- a/include/net/dst.h
+++ b/include/net/dst.h
@@ -57,7 +57,6 @@
 #define DST_XFRM_TUNNEL		0x0080
 #define DST_XFRM_QUEUE		0x0100
 #define DST_METADATA		0x0200
-#define DST_NOGC		0x0400
 
 	short			error;
 
@@ -336,10 +335,7 @@
  */
 static inline bool dst_hold_safe(struct dst_entry *dst)
 {
-	if (dst->flags & (DST_NOCACHE | DST_NOGC))
-		return atomic_inc_not_zero(&dst->__refcnt);
-	dst_hold(dst);
-	return true;
+	return atomic_inc_not_zero(&dst->__refcnt);
 }
 
 /**