SYSFS: Fix missing include of list.h in sysfs.h

Sysfs.h uses definitions (e.g. struct list_head s_sibling) from list.h
but does not include it.

Signed-off-by: Frank Haverkamp <haver@vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>