CHROMIUM: clocksource: allow clocksources to be selected earlier duri…
…ng boot

Global and per-CPU timers ought to be initialized once SMP initialization
is complete.  Although the clocksources associated with these timers may
not be registered until later in the boot process, they should be ready
to go once registered.  We'd like to stop using the super low-resolution
boot clocksource (jiffies) as soon as possible since devices may rely on
accurate timekeeping while being brought up during boot, so move
clocksource_done_booting() to arch_initcall time so that we can switch
to a higher-resolution clocksrouce earlier in the boot process.

BUG=chrome-os-partner:20458
TEST=Pit and Lumpy both still boot reliably.  Boot time on Pit improves
considerably:
Before: [    3.032967] VFS: Mounted root ...
After:  [    1.855936] VFS: Mounted root ...
Lumpy boot time improves very slightly:
Before: [    1.786347] VFS: Mounted root ...
After:  [    1.754297] VFS: Mounted root ...

Change-Id: I951fee2e7e4697ccfe7f845a2c1c6bd80669a8d5
Signed-off-by: Andrew Bresticker <abrestic@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/170102
Reviewed-by: Sonny Rao <sonnyrao@chromium.org>
Reviewed-by: Sameer Nanda <snanda@chromium.org>
Signed-off-by: Luis Cruz <ljc2491@gmail.com>
Signed-off-by: poondog <markj338@gmail.com>
fix previous commit derp