ARM: dts: stm32: add st,stm32-sdmmc2 compatible on stm32mp151

To align with bootloaders device tree files, and thanks to what was
added in yaml file [1], the compatible property for sdmmc nodes is
updated with "st,stm32-sdmmc2" string.

[1] commit 552bc464 ("dt-bindings: mmc: mmci: Add st,stm32-sdmmc2
    compatible")
Signed-off-by: NYann Gautier <yann.gautier@foss.st.com>
Signed-off-by: NAlexandre Torgue <alexandre.torgue@foss.st.com>

arch/arm/boot/dts/stm32mp151.dtsi

@@ -1059,7 +1059,7 @@
 		};
 
 		sdmmc3: mmc@48004000 {
-			compatible = "arm,pl18x", "arm,primecell";
+			compatible = "st,stm32-sdmmc2", "arm,pl18x", "arm,primecell";
 			arm,primecell-periphid = <0x00253180>;
 			reg = <0x48004000 0x400>;
 			interrupts = <GIC_SPI 137 IRQ_TYPE_LEVEL_HIGH>;
@@ -1381,7 +1381,7 @@
 		};
 
 		sdmmc1: mmc@58005000 {
-			compatible = "arm,pl18x", "arm,primecell";
+			compatible = "st,stm32-sdmmc2", "arm,pl18x", "arm,primecell";
 			arm,primecell-periphid = <0x00253180>;
 			reg = <0x58005000 0x1000>;
 			interrupts = <GIC_SPI 49 IRQ_TYPE_LEVEL_HIGH>;
@@ -1396,7 +1396,7 @@
 		};
 
 		sdmmc2: mmc@58007000 {
-			compatible = "arm,pl18x", "arm,primecell";
+			compatible = "st,stm32-sdmmc2", "arm,pl18x", "arm,primecell";
 			arm,primecell-periphid = <0x00253180>;
 			reg = <0x58007000 0x1000>;
 			interrupts = <GIC_SPI 124 IRQ_TYPE_LEVEL_HIGH>;