USB: cdc: add serial-state defines

Add defines for the serial-state bitmap values from section 6.3.5
SerialState of the CDC specification version 1.1.

Note that the bTxCarrier and bRxCarrier bits have been named after their
RS-232 signal equivalents DSR and DCD.
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20220725075841.1187-3-johan@kernel.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

include/uapi/linux/usb/cdc.h

@@ -306,6 +306,15 @@ struct usb_cdc_notification {
 	__le16	wLength;
 } __attribute__ ((packed));
 
+/* UART State Bitmap Values from 6.3.5 SerialState */
+#define USB_CDC_SERIAL_STATE_DCD		(1 << 0)
+#define USB_CDC_SERIAL_STATE_DSR		(1 << 1)
+#define USB_CDC_SERIAL_STATE_BREAK		(1 << 2)
+#define USB_CDC_SERIAL_STATE_RING_SIGNAL	(1 << 3)
+#define USB_CDC_SERIAL_STATE_FRAMING		(1 << 4)
+#define USB_CDC_SERIAL_STATE_PARITY		(1 << 5)
+#define USB_CDC_SERIAL_STATE_OVERRUN		(1 << 6)
+
 struct usb_cdc_speed_change {
 	__le32	DLBitRRate;	/* contains the downlink bit rate (IN pipe) */
 	__le32	ULBitRate;	/* contains the uplink bit rate (OUT pipe) */