This is just an alias for container_of() and it is used only
on a commented code. The commented code actually is an issue that
require fixes, so, move the container_of() call to the commented
code, and drop the unused function.

This way, a fix for the function could be added later without
needing to re-add to_state() function.

This fixes a clang W=1 warning.

Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>