kconfig: Hide error output in find command in streamline_config.pl

Finding the list of Makefiles in streamline-config should not report errors.

Also move the "chomp" to the @makefiles array instead of doing it in the
for loop. This is more efficient, and does not make it any less readable
by C programmers.

Signed-off-by: Toralf Foerster <toralf.foerster@gmx.de>
LKML-Reference: <201005262022.02928.toralf.foerster@gmx.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>