Clean-up try_to_wake_up().

Get rid of the 'new_cpu' variable in try_to_wake_up() [ that's, one
#ifdef section less ].  Also remove a few redundant blank lines.
Signed-off-by: NDmitry Adamushko <dmitry.adamushko@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>