kconfig: detect recursive inclusion earlier

Currently, the recursive inclusion is not detected when the offending
file is about to be included; it is detected the offending file is
about to include the *next* file.  This is because the detection loop
does not involve the file being included.

Do this check against the file that is about to be included so that
the recursive inclusion is detected before unneeded parsing happens.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>