tools: moveconfig: warn loudly if moved option has no entry in Kconfig
Currently, the tool gives up moving an option quietly if its entry
was not found in Kconfig.
If the option is not defined in the config header in the first
place, it is no problem (as the Kconfig entry may have been hidden
by reasonable "depends on").
However, if the option is defined in the config header, the missing
Kconfig entry is a sign of possible behavior change. It is highly
recommended to manually check if the option has been moved as
expected. In this case, let's add "suspicious" in the log and
change the log color (if --color option is given) to make it stand
out.