serial: stm32f7: disable overrun

With overrun enabled, serial port console freezes & stops receiving data with
overun error if we keep sending data.

Signed-off-by: Vikas Manocha <vikas.manocha@st.com>

drivers/serial/serial_stm32x7.c

@@ -93,6 +93,9 @@ static int stm32_serial_probe(struct udevice *dev)
 	}
 #endif
 
+	/* Disable usart-> disable overrun-> enable usart */
+	clrbits_le32(&usart->cr1, USART_CR1_RE | USART_CR1_TE | USART_CR1_UE);
+	setbits_le32(&usart->cr3, USART_CR3_OVRDIS);
 	setbits_le32(&usart->cr1, USART_CR1_RE | USART_CR1_TE | USART_CR1_UE);
 
 	return 0;

drivers/serial/serial_stm32x7.h

@@ -27,6 +27,8 @@ struct stm32_usart {
 #define USART_CR1_TE			(1 << 3)
 #define USART_CR1_UE			(1 << 0)
 
+#define USART_CR3_OVRDIS		(1 << 12)
+
 #define USART_SR_FLAG_RXNE		(1 << 5)
 #define USART_SR_FLAG_TXE		(1 << 7)