x86: do not promote TM3x00/TM5x00 to i686-class

We have been promoting Transmeta TM3x00/TM5x00 chips to i686-class
based on the notion that they contain all the user-space visible
features of an i686-class chip.  However, this is not actually true:
they lack the EA-taking long NOPs (0F 1F /0).  Since this is a
userspace-visible incompatibility, downgrade these CPUs to the
manufacturer-defined i586 level.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>