kconfiglib: Update to hide tracebacks for expected errors

Update Kconfiglib to upstream revision 9c0b562c94 to get this commit in:

    Add Kconfig.__init__() helper flag for suppressing tracebacks

    Tools that don't use standard_kconfig() currently generate spammy
    tracebacks for e.g. syntax errors.

    Add a suppress_traceback flag to Kconfig.__init__() for catching
    "expected" exceptions and printing them to stderr and exiting with
    status 1. Use it to make all tools consistently hide tracebacks.

Use the new flag to hide tracebacks for expected exceptions in
kconfig.py, lint.py, and genrest.py.

Some menuconfig robustness tweaks for wonky terminals are included as
well, and a new feature for customizing .config and autoconf.h header
comments via environment variables.

Signed-off-by: Ulf Magnusson <Ulf.Magnusson@nordicsemi.no>