serial: sirf: Use generic uart-has-rtscts DT property

Convert the SiRF UART driver from using the vendor-specific
"sirf,uart-has-rtscts" to the generic "uart-has-rtscts" DT property, as
documented by the Generic Serial DT Bindings.

The old vendor-specific property is still recognized by the driver for
backwards compatibility, but deprecated.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/tty/serial/sirfsoc_uart.c b/drivers/tty/serial/sirfsoc_uart.c
index 1d1c0b9..b186c9c 100644
--- a/drivers/tty/serial/sirfsoc_uart.c
+++ b/drivers/tty/serial/sirfsoc_uart.c
@@ -1293,7 +1293,8 @@
 	sirfport->uart_reg = (struct sirfsoc_uart_register *)match->data;
 
 	sirfport->hw_flow_ctrl =
-		of_property_read_bool(np, "sirf,uart-has-rtscts");
+		of_property_read_bool(np, "uart-has-rtscts") ||
+		of_property_read_bool(np, "sirf,uart-has-rtscts") /* deprecated */;
 	if (of_device_is_compatible(np, "sirf,prima2-uart") ||
 		of_device_is_compatible(np, "sirf,atlas7-uart"))
 		sirfport->uart_reg->uart_type = SIRF_REAL_UART;