cpu/intel/speedstep: Fix the PNOT ACPI method

The PNOT method never notifies the CPU to update it's _CST methods due
to reliance on inexisting variable (PDCx).

Add a method in the speedstep ssdt generator to notify all available
CPU nodes and hook this up in this file.

The cpu.asl file is moved to cpu/intel/speedstep/acpi since it now
relies on code generated in the speedstep ssdt generator. CPUs not
using the speedstep code never included this PNOT method so this is
a logical place for this code to be.

Change-Id: Ie2ba5e07b401d6f7c80c31f2bfcd9ef3ac0c1ad1
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/23144
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

src/arch/x86/include/arch/acpigen.h

@@ -82,6 +82,7 @@ enum {
 	AND_OP			= 0x7B,
 	OR_OP			= 0x7D,
 	NOT_OP			= 0x80,
+	NOTIFY_OP		= 0x86,
 	LEQUAL_OP		= 0x93,
 	LGREATER_OP		= 0x94,
 	LLESS_OP		= 0x95,