media: Revert "media: em28xx: add missing em28xx_close_extension"

This reverts commit 2c98b8a3.

Reverted patch causes problems with Hauppauge WinTV dualHD as Maximilian
reported [1]. Since quick solution didn't come up let's just revert it
to make this device work with upstream kernels.

Link: https://lore.kernel.org/all/6a72a37b-e972-187d-0322-16336e12bdc5@elbmurf.de/

 [1]

Reported-by: Maximilian Böhm <maximilian.boehm@elbmurf.de>
Tested-by: Maximilian Böhm <maximilian.boehm@elbmurf.de>
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>