rpaphp: compiler warning cleanup

This janitorial patch removes the following annoying
compile-time message:

drivers/pci/hotplug/rpaphp_slot.c:57: warning: ignoring return
value of sfs_create_file declared with attribute warn_unused_result

It also fixes a typo, removes some misc crud.

Signed-off-by: Linas Vepstas <linas@austin.ibm.com>
Cc: John Rose <johnrose@us.ibm.com>
Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>