USB: serial gadget: descriptor cleanup

Bugfix some serial gadget descriptors:

- Stop mangling the low bits (controller type ID) of bcdDevice;
just use the high bits for a driver revision code.

- Serial numbers that aren't specific to individual devices
are useless; stop reporting "0" for this.

- Since it's not part of a CDC-conformant function, the "bulk only"
configuration shouldn't be using "CDC Data" as its interface class.
Switch over to using CLASS_VENDOR_SPEC (different value, 0xff).

Signed-off-by: David Brownell <[e-mail]>
Cc: Al Borchers <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/gadget/serial.c

···
 /* Defines */
 
 #define GS_VERSION_STR			"v2.2"
-#define GS_VERSION_NUM			0x0202
+#define GS_VERSION_NUM			0x2200
 
 #define GS_LONG_NAME			"Gadget Serial"
 #define GS_SHORT_NAME			"g_serial"
···
 static struct usb_string gs_strings[] = {
 	{ GS_MANUFACTURER_STR_ID, manufacturer },
 	{ GS_PRODUCT_STR_ID, GS_LONG_NAME },
-	{ GS_SERIAL_STR_ID, "0" },
 	{ GS_BULK_CONFIG_STR_ID, "Gadget Serial Bulk" },
 	{ GS_ACM_CONFIG_STR_ID, "Gadget Serial CDC ACM" },
 	{ GS_CONTROL_STR_ID, "Gadget Serial Control" },
···
 	.idProduct =		__constant_cpu_to_le16(GS_PRODUCT_ID),
 	.iManufacturer =	GS_MANUFACTURER_STR_ID,
 	.iProduct =		GS_PRODUCT_STR_ID,
-	.iSerialNumber =	GS_SERIAL_STR_ID,
 	.bNumConfigurations =	GS_NUM_CONFIGS,
 };
 
···
 	.bDescriptorType =	USB_DT_INTERFACE,
 	.bInterfaceNumber =	GS_BULK_INTERFACE_ID,
 	.bNumEndpoints =	2,
-	.bInterfaceClass =	USB_CLASS_CDC_DATA,
+	.bInterfaceClass =	USB_CLASS_VENDOR_SPEC,
 	.bInterfaceSubClass =	0,
 	.bInterfaceProtocol =	0,
 	.iInterface =		GS_DATA_STR_ID,