ARM: dts: imx28: Use generic uart-has-rtscts DT property

As of commit 182cdcb8 ("serial: mxs-auart: Use generic
uart-has-rtscts DT property"), the Freescale MXS AUART driver recognizes
the generic "uart-has-rtscts" DT property, deprecating the
vendor-specific "fsl,uart-has-rtscts" DT property. Hence replace the
latter by the former in all DTS files.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NShawn Guo <shawnguo@kernel.org>

arch/arm/boot/dts/imx28-apf28dev.dts

@@ -140,7 +140,7 @@
 			auart0: serial@8006a000 {
 				pinctrl-names = "default";
 				pinctrl-0 = <&auart0_pins_a>;
-				fsl,uart-has-rtscts;
+				uart-has-rtscts;
 				status = "okay";
 			};
 

arch/arm/boot/dts/imx28-evk.dts

@@ -224,7 +224,7 @@
 			auart0: serial@8006a000 {
 				pinctrl-names = "default";
 				pinctrl-0 = <&auart0_pins_a>;
-				fsl,uart-has-rtscts;
+				uart-has-rtscts;
 				status = "okay";
 			};