media: dib0700: remove orphan dvb_usb_dib0700_ir_proto declaration

The dvb_usb_dib0700_ir_proto has been removed by
commit 0ffd1ab3 ("V4L/DVB: dib0700: properly implement IR
change_protocol"), so remove the orphan declaration.

Link: https://lore.kernel.org/linux-media/20220920015902.785337-1-cuigaosheng1@huawei.comSigned-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

drivers/media/usb/dvb-usb/dib0700.h

@@ -72,7 +72,6 @@ int dib0700_set_i2c_speed(struct dvb_usb_device *d, u16 scl_kHz);
 
 extern struct i2c_algorithm dib0700_i2c_algo;
 extern int dib0700_device_count;
-extern int dvb_usb_dib0700_ir_proto;
 extern struct dvb_usb_device_properties dib0700_devices[];
 extern struct usb_device_id dib0700_usb_id_table[];