[NTOSKRNL]

[NTOSKRNL]
- Rewrite IopIsAcpiComputer (and rename to IopIsFirmwareMapperDisabled) to eliminate the need for the ENABLE_ACPI define
- IopIsFirmwareMapperDisabled now reads the registry entry that HAL sets to indicate that the firmware mapper should be disabled
- Partially rewrite IopUpdateRootKey so it does not interfere with HAL's PnP driver
- ACPI is automatically enabled when the ACPI HAL is loaded and disabled when the standard HAL is loaded

svn path=/trunk/; revision=53249