KVM: PPC: Remove the tasklet used by the hrtimer

Powerpc timer implementation is a copycat version of s390. Now that they removed
the tasklet with commit ea74c0ea follow this
optimization.

Signed-off-by: Mihai Caraman <mihai.caraman@freescale.com>
Signed-off-by: Bogdan Purcareata <bogdan.purcareata@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>