[ACPI] Add support for FADT P_LVL2_UP flag

which tells us if C2 is valid for UP-only, or SMP.

As there is no separate bit for C3,  use P_LVL2_UP
bit to cover both C2 and C3.

http://bugzilla.kernel.org/show_bug.cgi?id=5165

Signed-off-by: Venkatesh Pallipadi<venkatesh.pallipadi@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
(cherry picked from 28b86b368af3944eb383078fc5797caf2dc8ce44 commit)