Checking "user" before "is_idle_task()" allows better optimizations
in cases where inlining is possible.  Also, "bool" should be passed
"true" or "false" rather than "1" or "0".  This commit therefore makes
these changes, as noted in Josh's review.

Reported-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>