ARM: dts: STi: Add fake reg property for miphy28lp_phy

Add fake reg property to miphy28lp_phy.
This allows to fix the following warning when compiling
dtb with W=1 option:

arch/arm/boot/dts/stih407-b2120.dtb: Warning (simple_bus_reg):
Node /soc/miphy28lp missing or empty reg/ranges property

arch/arm/boot/dts/stih410-b2120.dtb: Warning (simple_bus_reg):
Node /soc/miphy28lp missing or empty reg/ranges property

arch/arm/boot/dts/stih410-b2260.dtb: Warning (simple_bus_reg):
Node /soc/miphy28lp missing or empty reg/ranges property

arch/arm/boot/dts/stih418-b2199.dtb: Warning (simple_bus_reg):
Node /soc/miphy28lp missing or empty reg/ranges property
Signed-off-by: Patrice Chotard <patrice.chotard@st.com>

arch/arm/boot/dts/stih407-family.dtsi

@@ -389,12 +389,13 @@ usb2_picophy0: phy1 {
 			reset-names = "global", "port";
 		};
 
-		miphy28lp_phy: miphy28lp {
+		miphy28lp_phy: miphy28lp@0 {
 			compatible = "st,miphy28lp-phy";
 			st,syscfg = <&syscfg_core>;
 			#address-cells	= <1>;
 			#size-cells	= <1>;
 			ranges;
+			reg = <0 0>;
 
 			phy_port0: port@9b22000 {
 				reg = <0x9b22000 0xff>,

arch/arm/boot/dts/stih410-b2260.dts

@@ -200,7 +200,7 @@ codec {
 			};
 		};
 
-		miphy28lp_phy: miphy28lp {
+		miphy28lp_phy: miphy28lp@0 {
 
 			phy_port1: port@9b2a000 {
 				st,osc-force-ext;

arch/arm/boot/dts/stih418-b2199.dts

@@ -88,7 +88,7 @@ mmc0: sdhci@9060000 {
 			non-removable;
 		};
 
-		miphy28lp_phy: miphy28lp {
+		miphy28lp_phy: miphy28lp@0 {
 
 			phy_port0: port@9b22000 {
 				st,osc-rdy;

arch/arm/boot/dts/stihxxx-b2120.dtsi

@@ -80,7 +80,7 @@ hdmiddc: i2c@9541000 {
 			st,i2c-min-sda-pulse-width-us = <5>;
 		};
 
-		miphy28lp_phy: miphy28lp {
+		miphy28lp_phy: miphy28lp@0 {
 
 			phy_port0: port@9b22000 {
 				st,osc-rdy;