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 <[e-mail]>
Acked-by: Rob Herring <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

Documentation/devicetree/bindings/serial/sirf-uart.txt

···
 - clocks : Should contain uart clock number
 
 Optional properties:
-- sirf,uart-has-rtscts: we have hardware flow controller pins in hardware
-- rts-gpios: RTS pin for USP-based UART if sirf,uart-has-rtscts is true
-- cts-gpios: CTS pin for USP-based UART if sirf,uart-has-rtscts is true
+- uart-has-rtscts: we have hardware flow controller pins in hardware
+- rts-gpios: RTS pin for USP-based UART if uart-has-rtscts is true
+- cts-gpios: CTS pin for USP-based UART if uart-has-rtscts is true
 
 Example:
 
···
 
 usp@b0090000 {
 	compatible = "sirf,prima2-usp-uart";
-	sirf,uart-has-rtscts;
+	uart-has-rtscts;
 	rts-gpios = <&gpio 15 0>;
 	cts-gpios = <&gpio 46 0>;
 };

drivers/tty/serial/sirfsoc_uart.c

···
 	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;