northbridge/amd/amdht: Allow mainboards to set HT frequency limit

This is useful when the PCB layout of a mainboard does not allow
stable operation at the increased HyperTransport speeds of newer
processors.

Change-Id: Idc93a1294608178ddf38ca72d40e6bad7deb9004
Signed-off-by: Timothy Pearson <tpearson@raptorengineeringinc.com>
Reviewed-on: http://review.coreboot.org/8464
Tested-by: build bot (Jenkins)
Reviewed-by: Marc Jones <marc.jones@se-eng.com>
4 files changed