ARM: dts: stm32: Repair SDMMC2 operation

The eMMC uses different pinmux for the top four data lines, use such
a pinmux, otherwise it takes a very long time until the test for 8bit
operation times out. And this is the correct pinmux per schematic too.

Reviewed-by: Patrice Chotard <patrice.chotard@st.com>
Reviewed-by: Patrick Delaunay <patrick.delaunay@st.com>
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Cc: Patrick Delaunay <patrick.delaunay@st.com>
Cc: Patrice Chotard <patrice.chotard@st.com>
diff --git a/arch/arm/dts/stm32mp157a-avenger96-u-boot.dtsi b/arch/arm/dts/stm32mp157a-avenger96-u-boot.dtsi
index 47bfbb8..2c7dc50 100644
--- a/arch/arm/dts/stm32mp157a-avenger96-u-boot.dtsi
+++ b/arch/arm/dts/stm32mp157a-avenger96-u-boot.dtsi
@@ -174,7 +174,7 @@
 	};
 };
 
-&sdmmc2_d47_pins_a {
+&sdmmc2_d47_pins_b {
 	u-boot,dm-spl;
 	pins {
 		u-boot,dm-spl;