> Will it be more explicit if we call it HAS_CONFIG(XXX) ? Or HAS_KCONFIG(XXX)
> CONFIG(XXX) seems too generic to me that some drivers may wan to use it for wrapping a reference to config tables, like GPIO(XXX).

Hmm... I would really like to keep it as short as possible, and that's
another 4 chars. Also, I feel HAS_CONFIG may be a bit confusing (e.g.
may sound more like whether the config is used at all in a particular
board/SoC/arch, rather than whether it is enabled). I guess we could
go with KCONFIG(XXX) if you prefer, but I kinda liked the symmetry
between CONFIG_XXX and CONFIG(XXX).