USB: cdc: add control-signal defines

Add defines for the Control Signal Bitmap Values from section 6.2.14
SetControlLineState of the CDC specification version 1.1.
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20220725075841.1187-2-johan@kernel.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

include/uapi/linux/usb/cdc.h

@@ -271,6 +271,10 @@ struct usb_cdc_line_coding {
 	__u8	bDataBits;
 } __attribute__ ((packed));
 
+/* Control Signal Bitmap Values from 6.2.14 SetControlLineState */
+#define USB_CDC_CTRL_DTR			(1 << 0)
+#define USB_CDC_CTRL_RTS			(1 << 1)
+
 /* table 62; bits in multicast filter */
 #define	USB_CDC_PACKET_TYPE_PROMISCUOUS		(1 << 0)
 #define	USB_CDC_PACKET_TYPE_ALL_MULTICAST	(1 << 1) /* no filter */