ARM: dts: stm32: fix AV96 board SAI2 pin muxing on stm32mp15

Fix SAI2A and SAI2B pin muxings for AV96 board on STM32MP15.
Change sai2a-4 & sai2a-5 to sai2a-2 & sai2a-2.
Change sai2a-4 & sai2a-sleep-5 to sai2b-2 & sai2b-sleep-2

Fixes: dcf185ca ("ARM: dts: stm32: Add alternate pinmux for SAI2 pins on stm32mp15")
Signed-off-by: Olivier Moysan <olivier.moysan@foss.st.com>
Reviewed-by: Marek Vasut <marex@denx.de>
Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com>

arch/arm/boot/dts/stm32mp15-pinctrl.dtsi

@@ -1179,7 +1179,7 @@ pins {
 		};
 	};
 
-	sai2a_pins_c: sai2a-4 {
+	sai2a_pins_c: sai2a-2 {
 		pins {
 			pinmux = <STM32_PINMUX('D', 13, AF10)>, /* SAI2_SCK_A */
 				 <STM32_PINMUX('D', 11, AF10)>, /* SAI2_SD_A */
@@ -1190,7 +1190,7 @@ pins {
 		};
 	};
 
-	sai2a_sleep_pins_c: sai2a-5 {
+	sai2a_sleep_pins_c: sai2a-2 {
 		pins {
 			pinmux = <STM32_PINMUX('D', 13, ANALOG)>, /* SAI2_SCK_A */
 				 <STM32_PINMUX('D', 11, ANALOG)>, /* SAI2_SD_A */
@@ -1235,14 +1235,14 @@ pins {
 		};
 	};
 
-	sai2b_pins_c: sai2a-4 {
+	sai2b_pins_c: sai2b-2 {
 		pins1 {
 			pinmux = <STM32_PINMUX('F', 11, AF10)>; /* SAI2_SD_B */
 			bias-disable;
 		};
 	};
 
-	sai2b_sleep_pins_c: sai2a-sleep-5 {
+	sai2b_sleep_pins_c: sai2b-sleep-2 {
 		pins {
 			pinmux = <STM32_PINMUX('F', 11, ANALOG)>; /* SAI2_SD_B */
 		};