acpiphp: fix missing acpiphp_glue_exit()

acpiphp_glue_exit() needs to be called to unwind when no slots found.
(It fixes data corruption when reloading acpiphp driver with no such devices)

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>