Revert "media: cec: core: add adap_nb_transmit_canceled() callback"

This reverts commit a896c674 which is
commit da53c36d 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: I1ea895e4c9b1dc05aa46673722aa81ede779df65
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>