dt-bindings: Add include/dt-bindings/phy/phy.h from Linux v4.4

This will be needed by the upcoming Marvell Armada 375 dts files.

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Luka Perkov <luka.perkov@sartura.hr>

include/dt-bindings/phy/phy.h

+/*
+ *
+ * This header provides constants for the phy framework
+ *
+ * Copyright (C) 2014 STMicroelectronics
+ * Author: Gabriel Fernandez <gabriel.fernandez@st.com>
+ * License terms:  GNU General Public License (GPL), version 2
+ */
+
+#ifndef _DT_BINDINGS_PHY
+#define _DT_BINDINGS_PHY
+
+#define PHY_NONE		0
+#define PHY_TYPE_SATA		1
+#define PHY_TYPE_PCIE		2
+#define PHY_TYPE_USB2		3
+#define PHY_TYPE_USB3		4
+
+#endif /* _DT_BINDINGS_PHY */