tools: moveconfig: show suspicious boards with possible misconversion

There are some cases where config options are moved, but they are
ripped off at the final savedefconfig stage:

  - The moved option is not user-configurable, for example, due to
    a missing prompt in the Kconfig entry

  - The config was not defined in the original config header despite
    the Kconfig specifies it as non-bool type

  - The config define in the header contains reference to another
    macro, for example:
        #define CONFIG_CONS_INDEX     (CONFIG_SYS_LPC32XX_UART - 2)
    The current moveconfig does not support recursive macro expansion.

In these cases, the conversion is very likely to be an unexpected
result.  That is why I decided to display the log in yellow color
in commit 5da4f857 ("tools: moveconfig: report when CONFIGs are
removed by savedefconfig").

It would be nice to display the list of suspicious boards when the
tool finishes processing.  It is highly recommended to check the
defconfigs once again when this message is displayed.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Joe Hershberger <joe.hershberger@ni.com>