Intel cpus: improve CPU compatibility of new CAR

Intel cpus: improve CPU compatibility of new CAR

Most or many Xeons have no MSR 0x11e.

I have previously tested that a HT-enabled P4 (model f25) can
execute this but will not have cache-as-ram enabled. Should work
for non-HT P4.

Change-Id: I28cbfa68858df45a69aa0d5b050cd829d070ad66
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: http://review.coreboot.org/644
Tested-by: build bot (Jenkins)
Reviewed-by: Idwer Vollering <vidwer@gmail.com>
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>