When we check if a GPE can be used for runtime signaling, we only
search the FADT GPE blocks, which is incorrect, becuase the GPE
may be located elsewhere.  We really should be using the GPE device
information previously returned by _PRW here, so make that happen.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Len Brown <len.brown@intel.com>