media: uvcvideo: Fix missing newline after declarations

Fixes 'Missing a blank line after declarations' warning issued by
scripts/checkpatch.pl on drivers/media/usb/uvc/uvc_driver.c

Signed-off-by: Pedro Guilherme Siqueira Moreira <pedro.guilherme@espectro.eng.br>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>