As of Change-Id: I780d34ded2c1e3737ae1af685c8c2da832842e7c the
reference clock can be 100Mhz.
Decode the register and use the reference clock to calculate
the selected DDR frequency.
Tested on Lenovo T430.
Change-Id: I8481564fe96af29ac31482a7f03bb88f343326f4
Signed-off-by: Patrick Rudolph <siro@das-labor.org>
Reviewed-on: https://review.coreboot.org/19995
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
6ab7e5e090