serial: stm32: correct flow control property spelling

"st,hw-flow-ctrl" property is documented in device tree
binding whereas "auto-flow-control" was used in the code.
The driver is now aligned with the binding name
"st,hw-flow-ctrl".

Signed-off-by: Gerald Baeza <gerald.baeza@st.com>
Signed-off-by: Alexandre TORGUE <alexandre.torgue@st.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index 184b018..ab294b9 100644
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -508,7 +508,7 @@
 		return NULL;
 
 	stm32_ports[id].hw_flow_control = of_property_read_bool(np,
-							"auto-flow-control");
+							"st,hw-flow-ctrl");
 	stm32_ports[id].port.line = id;
 	return &stm32_ports[id];
 }