The variable 'system_kset' is only referenced in this file and
should be marked static to prevent it from being exposed globally.

This quiets the sparse waring:

warning: symbol 'system_kset' was not declared. Should it be static?

Also, remove the comment since drivers/base/sys.c has now been
deleted.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>