Revert "media: cec: use call_op and check for !unregistered"

This reverts commit 73ef9ae9 which is
commit e2ed5024 upstream.

It breaks the Android kernel abi and can be brought back in the future
in an abi-safe way if it is really needed.

Bug: 161946584
Change-Id: Iad22e062acb2b9ce3f45eb55fdf6e4ea42e7fb01
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>