arm64: dts: salvator-x: SCIF1 supports RTS/CTS hardware flow control

On the Salvator-X development board, the RTS and CTS pins of debug
serial-1 port SCIF1 are wired to the CP2102 Serial-USB bridge.  Reflect
this in the DTS by adding the "uart-has-rtscts" property to the scif1
device node.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm64/boot/dts/renesas/r8a7795-salvator-x.dts

@@ -208,6 +208,7 @@ &scif1 {
 	pinctrl-0 = <&scif1_pins>;
 	pinctrl-names = "default";
 
+	uart-has-rtscts;
 	status = "okay";
 };