freezer: shorten freezer sleep time using exponential backoff

All tasks can easily be frozen in under 10 ms, switch to using
an initial 1 ms sleep followed by exponential backoff until
8 ms.  Also convert the printed time to ms instead of centiseconds.

Signed-off-by: Colin Cross <ccross@android.com>
modified for Mako hybrid from LKML

Signed-off-by: Paul Reioux <reioux@gmail.com>

Conflicts:
kernel/power/process.c

idea is taken here -
https://github.com/faux123/htc-m7/commit/02e4802a6a91d6e686ff4532f11b9b0567a45a47