Revert "media: cec-adap.c: drop activate_cnt, use state info instead"

This reverts commit 3e938b7d which is
commit f9222f8c 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: I6094dc863dce57345f6aea43bb58ddb2c27ebf1a
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>