net/dcb: Add dscp to priority selector type

IEEE specification P802.1Qcd/D2.1 defines priority selector 5.
This APP TLV selector defines DSCP to priority map.
This patch defines such DSCP selector.
Signed-off-by: Huy Nguyen <huyn@mellanox.com>
Reviewed-by: Parav Pandit <parav@mellanox.com>
Reviewed-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

include/uapi/linux/dcbnl.h

@@ -206,6 +206,7 @@ struct cee_pfc {
 #define IEEE_8021QAZ_APP_SEL_STREAM	2
 #define IEEE_8021QAZ_APP_SEL_DGRAM	3
 #define IEEE_8021QAZ_APP_SEL_ANY	4
+#define IEEE_8021QAZ_APP_SEL_DSCP       5
 
 /* This structure contains the IEEE 802.1Qaz APP managed object. This
  * object is also used for the CEE std as well.