cpu/intel/model_6ex: Set msr bits for dynamic L2, C2E, C4E
The datasheets "Intel® Core™ Duo Processor and Intel® Core™ Solo
Processor on 65 nm Process" mentions cpu C-states substates which can
either be attained by adding a substate hint to the MWAIT/P_LVLx request
or automatically by setting some msr bits correctly.
This just sets the same msr bits as model_6fx to enable
dynamic L2 cache, C2E and C4E acpi cpu states.
The result is that when limiting a thinkpad x60 with a yonah T2400
cpu to the acpi cpu C2 state, the idle power usage drops from 18W to
14W. When the lowest C-state is set to C4 the idle power usage seems
to remain similar.
Change-Id: I6c422656ace04659f32082a5944617eda6c79ec3
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/16901
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>