ARM: DT: STi: STiH418: Add miphy28lp optional oscillator clock properties

STiH418 miphy28lp port0/1 need the oscillator clock configured in the same way
as on STiH407/STiH410 platforms.
Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
Signed-off-by: Maxime Coquelin <maxime.coquelin@st.com>

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

@@ -86,5 +86,16 @@ mmc0: sdhci@09060000 {
 			sd-uhs-sdr104;
 			sd-uhs-ddr50;
 		};
+
+		miphy28lp_phy: miphy28lp@9b22000 {
+
+			phy_port0: port@9b22000 {
+				st,osc-rdy;
+			};
+
+			phy_port1: port@9b2a000 {
+				st,osc-force-ext;
+			};
+		};
 	};
 };