Revert "kconfig: tristate choices with mixed tristate and boolean values"

This reverts commit a5bf3d89.

David Brownell notes that this causes a regression visible in the
drivers/usb/gadget Kconfig file:

  "That Kconfig hasn't changed (other than adding new drivers), and it's
   worked that way for several years now ...  so the issue seems to be
   changes in menuconfig/kconfig/etc semantics.

   The issue is that when USB_GADGET=m, it's no longer possible to
   configure peripheral controller drivers as modules ...  the
   controller drivers can now only be configured for static linkage.

   It should be making a choice of one of the controller drivers which
   could work on the target system, and allow that driver to be linked
   either as a module (ok iff USB_GADGET=m) or statically."

Reverting this commit resolves the problem, and also fixes a second
problem that David noticed: various dependent options couldn't be enabled.

Tested-and-reported-by: David Brownell <david-b@pacbell.net>
Cc: Randy Dunlap <rdunlap@xenotime.net>
Cc: Jan Beulich <jbeulich@novell.com>,
Cc: Andrew Morton <akpm@linux-foundation.org>,
Cc: Sam Ravnborg <sam@ravnborg.org>,
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>