vxlan: fix incorrect RCO bit in VXLAN header

Commit 3511494c ("vxlan: Group Policy extension") changed definition of
VXLAN_HF_RCO from 0x00200000 to BIT(24). This is obviously incorrect. It's
also in violation with the RFC draft.

Fixes: 3511494c ("vxlan: Group Policy extension")
Cc: Thomas Graf <tgraf@suug.ch>
Cc: Tom Herbert <therbert@google.com>
Signed-off-by: Jiri Benc <jbenc@redhat.com>
Acked-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/vxlan.h

@@ -79,7 +79,7 @@ struct vxlanhdr {
 };
 
 /* VXLAN header flags. */
-#define VXLAN_HF_RCO BIT(24)
+#define VXLAN_HF_RCO BIT(21)
 #define VXLAN_HF_VNI BIT(27)
 #define VXLAN_HF_GBP BIT(31)