sysfs: fix build errors: uevent with CONFIG_SYSFS=n

Fix source files to build with CONFIG_SYSFS=n.
module_subsys is not available.

SYSFS=n, MODULES=y:	T:y
SYSFS=n, MODULES=n:	T:y

SYSFS=y, MODULES=y:	T:y
SYSFS=y, MODULES=n:	T:y

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>