Rewritten driver along the lines of all the other new drivers,
implementing the new timer API. Structurally, the machine timer is an
up-counter with comparator, so it works broadly the same way HPET and
NRF do. The quirk here is that it's a 64 bit counter, which needs a
little more care.
Unlike the other timer reworks, this driver has grown by a few lines
as it used to be very simple. But in exchange, we get full tickless
support on the platform.
Fixes#10609 in the process (the 64 bit timer registers are unlatched
for sub-word transfers, so you have to use careful ordering).
Signed-off-by: Andy Ross <andrew.j.ross@intel.com>
f04f797c2b