kernel/panic.c: add TAINT_AUX

kernel/panic.c: add TAINT_AUX

This is the gist of a patch which we've been forward-porting in our
kernels for a long time now and it probably would make a good sense to
have such TAINT_AUX flag upstream which can be used by each distro etc,
how they see fit.  This way, we won't need to forward-port a distro-only
version indefinitely.

Add an auxiliary taint flag to be used by distros and others.  This
obviates the need to forward-port whatever internal solutions people
have in favor of a single flag which they can map arbitrarily to a
definition of their pleasing.

The "X" mnemonic could also mean eXternal, which would be taint from a
distro or something else but not the upstream kernel.  We will use it to
mark modules for which we don't provide support.  I.e., a really
eXternal module.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Borislav Petkov <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Jessica Yu <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Jiri Slaby <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Michal Marek <[email protected]>
Cc: Jiri Kosina <[email protected]>
Cc: Takashi Iwai <[email protected]>
Cc: Petr Mladek <[email protected]>
Cc: Jeff Mahoney <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>