kconfig: allow symbols implied by y to become m

The 'imply' keyword restricts a symbol to y or n, excluding m
when it is implied by y. This is the original behavior since
commit 237e3ad0f195 ("Kconfig: Introduce the "imply" keyword").

However, the author of this feature, Nicolas Pitre, stated that
the 'imply' keyword should not impose any restrictions.
(https://lkml.org/lkml/2020/2/19/714)

I agree, and want to get rid of this tricky behavior.

Suggested-by: Nicolas Pitre <[email protected]>
Signed-off-by: Masahiro Yamada <[email protected]>
Acked-by: Nicolas Pitre <[email protected]>
2 files changed