Trust the state of a power resource that get from a working _STA method
instead of trying to cache it.

Previously, we only trusted the state if we did not have a cached state.
However, once a state was cached, the _STA method was always ignored.
Specifically, once a power resource had been turned on once (e.g.
during resume), the driver assumed it was always on even if _STA said it
was off and never turned it back on.  This prevented the power resource
from being turned back on if a laptop was resumed twice, for example.

To fix, just remove the cached state entirely and always use the results
of _STA.  The loops already skip any resources where _STA fails.

Submitted by:	trasz (initial patch to invoke _ON)
MFC after:	1 week