ARM: dts: stm32: update eMMC configuration for stm32mp157c-ev1

Update the sdmmc2 node for eMMC support on eval board stm32mp157c-ev1.
- update slew-rate for pin configuration
- update "vqmmc-supply"
- remove "st,sig-dir"
- add mandatory "pinctrl-names"
- add "mmc-ddr-3_3v"

This patch solve the eMMC detection issue for command "mmc dev 1".

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
diff --git a/arch/arm/dts/stm32mp157c-ed1.dts b/arch/arm/dts/stm32mp157c-ed1.dts
index 73d07cf..bc4d7e1 100644
--- a/arch/arm/dts/stm32mp157c-ed1.dts
+++ b/arch/arm/dts/stm32mp157c-ed1.dts
@@ -294,15 +294,18 @@
 };
 
 &sdmmc2 {
+	pinctrl-names = "default", "opendrain", "sleep";
 	pinctrl-0 = <&sdmmc2_b4_pins_a &sdmmc2_d47_pins_a>;
+	pinctrl-1 = <&sdmmc2_b4_od_pins_a &sdmmc2_d47_pins_a>;
+	pinctrl-2 = <&sdmmc2_b4_sleep_pins_a &sdmmc2_d47_sleep_pins_a>;
 	non-removable;
 	no-sd;
 	no-sdio;
-	st,sig-dir;
 	st,neg-edge;
 	bus-width = <8>;
 	vmmc-supply = <&v3v3>;
-	vqmmc-supply = <&vdd>;
+	vqmmc-supply = <&v3v3>;
+	mmc-ddr-3_3v;
 	status = "okay";
 };