[media] em28xx: make em28xx-video to be a separate module

Now that all analog-specific code are at em28xx-video, convert
it into an em28xx extension and load it as a separate module.

Reviewed-by: Frank Schäfer <fschaefer.oss@googlemail.com>
Tested-by: Frank Schäfer <fschaefer.oss@googlemail.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

drivers/media/usb/em28xx/em28xx-vbi.c

@@ -27,6 +27,7 @@
 #include <linux/init.h>
 
 #include "em28xx.h"
+#include "em28xx-v4l.h"
 
 static unsigned int vbibufs = 5;
 module_param(vbibufs, int, 0644);