ARM: dts: stm32: Add alternate pinmux for FDCAN2 pins

Add another mux option for FDCAN2 pins, this is used on AV96 board.
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Patrice Chotard <patrice.chotard@st.com>
Cc: Patrick Delaunay <patrick.delaunay@st.com>
Cc: linux-stm32@st-md-mailman.stormreply.com
To: linux-arm-kernel@lists.infradead.org
Signed-off-by: Alexandre Torgue <alexandre.torgue@st.com>

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

@@ -793,6 +793,26 @@ pins {
 		};
 	};
 
+	m_can2_pins_a: m-can2-0 {
+		pins1 {
+			pinmux = <STM32_PINMUX('B', 13, AF9)>; /* CAN2_TX */
+			slew-rate = <1>;
+			drive-push-pull;
+			bias-disable;
+		};
+		pins2 {
+			pinmux = <STM32_PINMUX('B', 5, AF9)>; /* CAN2_RX */
+			bias-disable;
+		};
+	};
+
+	m_can2_sleep_pins_a: m_can2-sleep-0 {
+		pins {
+			pinmux = <STM32_PINMUX('B', 13, ANALOG)>, /* CAN2_TX */
+				 <STM32_PINMUX('B', 5, ANALOG)>; /* CAN2_RX */
+		};
+	};
+
 	pwm1_pins_a: pwm1-0 {
 		pins {
 			pinmux = <STM32_PINMUX('E', 9, AF1)>, /* TIM1_CH1 */