ACPICA: Remove obsolete Flags parameter.

Remove flags parameter for acpi_{get,set}_register().
It is no longer necessary now that these functions use a
spinlock for mutual exclusion.

Signed-off-by: Alexey Starikovskiy <alexey.y.starikovskiy@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>