dt-bindings: phy: Add PHY_TYPE_DP definition

Add definition for DisplayPort phy type.
Signed-off-by: Jyri Sarha <jsarha@ti.com>
Reviewed-by: Roger Quadros <rogerq@ti.com>
Reviewed-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>

include/dt-bindings/phy/phy.h

@@ -16,5 +16,6 @@
 #define PHY_TYPE_USB2		3
 #define PHY_TYPE_USB3		4
 #define PHY_TYPE_UFS		5
+#define PHY_TYPE_DP		6
 
 #endif /* _DT_BINDINGS_PHY */