KVM: PPC: Book3S: Remove load/put vcpu for KVM_GET_REGS/KVM_SET_REGS

In both HV and PR KVM, the KVM_SET_REGS/KVM_GET_REGS ioctl should
be able to perform without the vcpu loaded.

Since the vcpu mutex locking/unlock has been moved out of vcpu_load()
/vcpu_put(), KVM_SET_REGS/KVM_GET_REGS don't need to do ioctl with
the vcpu loaded anymore. This patch removes vcpu_load()/vcpu_put()
from KVM_SET_REGS/KVM_GET_REGS ioctl.

Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>