PCI: hotplug: acpiphp: fix slot poweroff problem on systems without _PS3

On systems where the optional _PS3 ACPI object is not implemented
acpiphp fails to power off the slot.  This is happening because the
current code does not attempt to remove power using the _EJ0 ACPI
object.  This patch restores the _EJ0 evaluation attempt which was
apparently inadvertently removed from the power-off sequence when the
_EJ0 evaluation code was relocated from power_off_slot() to
acpiphp_eject_slot().

Signed-off-by: Gary Hade <garyhade@us.ibm.com>
Cc: <lcm@us.ibm.com>
Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>