As Intel(TM) cpus are discovered to have more bugs, more workaround MSRs

As Intel(TM) cpus are discovered to have more bugs, more workaround MSRs
are added.  Presence of such MSRs is indicated with a feature flag, which
we probe and print at startup for each AP CPU.  EFI screen scrolling hasn't
gotten faster (yet) and 9600 baud serial console is still the same speed
as 1980.   Final piece of the puzzle is machines have more cpus, providing
more opportunity for screen scrolling and serial fifo's to fill up.  The
BSP cpu is watching the AP cpus probe and print, but increased latency
causes it to exceed a timeout and print "cpuXX: failed messages".
Crank that timeout.
discussed with kettenis, ok guenther