PM / Runtime: Move code in drivers/base/power/runtime.c

This patch (as1421) moves the PM runtime accounting subroutines up to
the beginning of runtime.c, taking them out of the middle of the
functions that do the actual work.  No operational changes.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>