media: gspca: fix Kconfig help info

Documentation/video4linux/gspca.txt is missing.
It has moved to Documentation/media/v4l-drivers/gspca-cardlist.rst
Signed-off-by: winton.liu <18502523564@163.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/usb/gspca/Kconfig

@@ -7,7 +7,7 @@ menuconfig USB_GSPCA
 	  Say Y here if you want to enable selecting webcams based
 	  on the GSPCA framework.
 
-	  See <file:Documentation/video4linux/gspca.txt> for more info.
+	  See <file:Documentation/media/v4l-drivers/gspca-cardlist.rst> for more info.
 
 	  This driver uses the Video For Linux API. You must say Y or M to
 	  "Video For Linux" to use this driver.