lscpu: show static and dynamic MHz (s390)

lscpu: show static and dynamic MHz (s390)

s390 machines provide static and dynamic cpu mhz information via
/proc/cpuinfo. The static cpu mhz is the normal cpu frequency a cpu is
supposed to run with.

The dynamic cpu mhz is the actual frequency a cpu is running
with. This is usually the same as the static cpu mhz. Note that this
values are different to the min/max mhz values available on other
architecutes. The min/max values are unknown.

This patch adds two new fields to the summary output which display
these two values.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>