scripts/decode_stacktrace.sh: handle symbols in modules

scripts/decode_stacktrace.sh presently displays module symbols as

	func+0x0ff/0x5153 [module]

Add a third argument: the pathname of a directory where the script
should look for the file module.ko so that the output appears as

	func (foo/bar.c:123) module

Without the argument or if the module file isn't found the script prints
such symbols as is without decoding.

Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>