kconfig: add named choice group

As choice dependency are now fully checked, it's quite easy to add support
for named choices. This lifts the restriction that a choice value can only
appear once, although it still has to be within the same group,
but multiple choices can be joined by giving them a name.
While at it I cleaned up a little the choice type logic to simplify it a
bit.

Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>

=======

Cherry-picked from the Linux kernel.

BUG=None
TEST=Built for Pit, Link, Fox.
BRANCH=None

Change-Id: I84f6400e9c64ee70a1e37f0872f66c860c7d7ba8
Signed-off-by: Gabe Black <gabeblack@google.com>
Reviewed-on: https://gerrit.chromium.org/gerrit/51061
Reviewed-by: Stefan Reinauer <reinauer@google.com>
Commit-Queue: Gabe Black <gabeblack@chromium.org>
Tested-by: Gabe Black <gabeblack@chromium.org>
6 files changed
tree: b3fc8af780de464c2cfda8dfbf545a89f1ba382b
  1. .gitignore
  2. Kconfig
  3. Makefile
  4. Makefile.inc
  5. PRESUBMIT.cfg
  6. board/
  7. src/
  8. util/