init: skip calibration delay if previously done

For each CPU, do the calibration delay only once.  For subsequent calls,
use the cached per-CPU value of loops_per_jiffy.

This saves about 200ms of resume time on dual core Intel Atom N5xx based
systems.  This helps bring down the kernel resume time on such systems
from about 500ms to about 300ms.

[akpm@linux-foundation.org: make cpu_loops_per_jiffy static]
[akpm@linux-foundation.org: clean up message text]
[akpm@linux-foundation.org: fix things up after upstream rmk changes]
Signed-off-by: Sameer Nanda <snanda@chromium.org>
Cc: Phil Carmody <ext-phil.2.carmody@nokia.com>
Cc: Andrew Worsley <amworsley@gmail.com>
Cc: David Daney <ddaney@caviumnetworks.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>