[PATCH] ACPI: Fix 2.6.21 boot regression on P4/HT

[PATCH] ACPI: Fix 2.6.21 boot regression on P4/HT

Up through 2.6.20 we cleared the FADT.CSTATE_CONTROL field
for FADT versions before r3, because it made no sense
for that reserved field to be set for pre-ACPI 2.0 systems.

It turns out that not clearing this field exposes
Linux to SMM BIOS failures, so do the same in 2.6.21.

http://bugzilla.kernel.org/show_bug.cgi?id=8346

Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>