cpud: don't print wait4 ENOCHLD messages
cpud: don't print wait4 ENOCHLD messages

Turns out Wait4 returns after one second with ENOCHLD.

Ignore those errors.

Signed-off-by: Ronald G. Minnich <f569d0af9a3481c4007b95c7180d6c41009f2513@gmail.com>

u-root/cpu,u-root/cpu,u-root/cpu