ARM: dts: STi: Remove unused clk_ext2f_a9 clock

This clock node is unused, remove it.
This allows to fix the following warnings when compiling
dtb with W=1 option :

arch/arm/boot/dts/stih410-b2120.dtb: Warning (simple_bus_reg):
Node /clocks/clockgen-c0 missing or empty reg/ranges property

arch/arm/boot/dts/stih410-b2260.dtb: Warning (simple_bus_reg):
Node /clocks/clockgen-c0 missing or empty reg/ranges property

arch/arm/boot/dts/stih418-b2199.dtb: Warning (simple_bus_reg):
Node /clocks/clockgen-c0 missing or empty reg/ranges property
Signed-off-by: Patrice Chotard <patrice.chotard@st.com>

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

@@ -71,17 +71,6 @@ arm_periph_clk: clk-m-a9-periphs {
 			};
 		};
 
-		/*
-		 * Bootloader initialized system infrastructure clock for
-		 * serial devices.
-		 */
-		clk_ext2f_a9: clockgen-c0 {
-			#clock-cells = <0>;
-			compatible = "fixed-clock";
-			clock-frequency = <200000000>;
-			clock-output-names = "clk-s-icn-reg-0";
-		};
-
 		clockgen-a@90ff000 {
 			compatible = "st,clkgen-c32";
 			reg = <0x90ff000 0x1000>;

arch/arm/boot/dts/stih410-clock.dtsi

@@ -71,17 +71,6 @@ arm_periph_clk: clk-m-a9-periphs {
 			};
 		};
 
-		/*
-		 * Bootloader initialized system infrastructure clock for
-		 * serial devices.
-		 */
-		clk_ext2f_a9: clockgen-c0 {
-			#clock-cells = <0>;
-			compatible = "fixed-clock";
-			clock-frequency = <200000000>;
-			clock-output-names = "clk-s-icn-reg-0";
-		};
-
 		clockgen-a@90ff000 {
 			compatible = "st,clkgen-c32";
 			reg = <0x90ff000 0x1000>;

arch/arm/boot/dts/stih418-clock.dtsi

@@ -72,17 +72,6 @@ arm_periph_clk: clk-m-a9-periphs {
 			};
 		};
 
-		/*
-		 * Bootloader initialized system infrastructure clock for
-		 * serial devices.
-		 */
-		clk_ext2f_a9: clockgen-c0 {
-			#clock-cells = <0>;
-			compatible = "fixed-clock";
-			clock-frequency = <200000000>;
-			clock-output-names = "clk-s-icn-reg-0";
-		};
-
 		clockgen-a@90ff000 {
 			compatible = "st,clkgen-c32";
 			reg = <0x90ff000 0x1000>;