kernel-chktaint: add reporting for tainted modules

kernel-chktaint: add reporting for tainted modules

Check all loaded modules and report any that have their 'taint'
flags set.  The tainted module output format is:
 * <module_name> (<taint_flags>)

Example output:

Kernel is "tainted" for the following reasons:
 * externally-built ('out-of-tree') module was loaded  (#12)
 * unsigned module was loaded (#13)
Raw taint value as int/string: 12288/'G           OE      '

Tainted modules:
 * dump_test (OE)

Link: https://lkml.kernel.org/r/20260115064756.531592-1-rdunlap@infradead.org
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Thorsten Leemhuis <linux@leemhuis.info>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>