KVM: s390: get rid of constant condition in ipte_unlock_simple

Due to the earlier check we know that ipte_lock_count must be 0.
No need to add a useless if. Let's make clear that we are going
to always wakeup when we execute that code.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>