ARM: dts: stm32: add i2c4 sleep pinctrl on stm32mp157c-ed1

Add the sleep state pinctrl entry for the i2c4 node
of the stm32mp157c-ed1 board.
Signed-off-by: Alain Volmat <alain.volmat@st.com>
Signed-off-by: Alexandre Torgue <alexandre.torgue@st.com>

arch/arm/boot/dts/stm32mp157c-ed1.dts

@@ -130,8 +130,9 @@ &gpu {
 };
 
 &i2c4 {
-	pinctrl-names = "default";
+	pinctrl-names = "default", "sleep";
 	pinctrl-0 = <&i2c4_pins_a>;
+	pinctrl-1 = <&i2c4_pins_sleep_a>;
 	i2c-scl-rising-time-ns = <185>;
 	i2c-scl-falling-time-ns = <20>;
 	clock-frequency = <400000>;