USB: serial: cp210x: use in-kernel types in port data

The port data is not exported to user space so use the in-kernel u8
type.

Link: https://lore.kernel.org/r/20200713105517.27796-6-johan@kernel.orgReviewed-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NJohan Hovold <johan@kernel.org>

drivers/usb/serial/cp210x.c

@@ -266,7 +266,7 @@ enum cp210x_event_state {
 };
 
 struct cp210x_port_private {
-	__u8			bInterfaceNumber;
+	u8			bInterfaceNumber;
 	bool			has_swapped_line_ctl;
 	bool			event_mode;
 	enum cp210x_event_state event_state;