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: I6c14452de87e35943c042c3a388c976e59e587a9
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>