ACPI: Fix D3hot v D3cold confusion

Before this patch, ACPI_STATE_D3 incorrectly referenced D3hot
in some places, but D3cold in other places.

After this patch, ACPI_STATE_D3 always means ACPI_STATE_D3_COLD;
and all references to D3hot use ACPI_STATE_D3_HOT.

ACPI's _PR3 method is used to enter both D3hot and D3cold states.
What distinguishes D3hot from D3cold is the presence _PR3
(Power Resources for D3hot)  If these resources are all ON,
then the state is D3hot.  If _PR3 is not present,
or all _PR0 resources for the devices are OFF,
then the state is D3cold.

This patch applies after Linux-3.4-rc1.
A future syntax cleanup may remove ACPI_STATE_D3
to emphasize that it always means ACPI_STATE_D3_COLD.

Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Reviewed-by: Aaron Lu <aaron.lu@amd.com>
Signed-off-by: Len Brown <len.brown@intel.com>