KVM: PPC: Remove comment saying SPRG1 is used for vcpu pointer

Scott Wood pointed out that We are no longer using SPRG1 for vcpu pointer,
but using SPRN_SPRG_THREAD <=> SPRG3 (thread->vcpu). So this comment
is not valid now.

Note: SPRN_SPRG3R is not supported (do not see any need as of now),
and if we want to support this in future then we have to shift to using
SPRG1 for VCPU pointer.
Signed-off-by: NBharat Bhushan <Bharat.Bhushan@freescale.com>
Signed-off-by: NAlexander Graf <agraf@suse.de>

arch/powerpc/include/asm/reg.h

@@ -944,9 +944,6 @@
  *      readable variant for reads, which can avoid a fault
  *      with KVM type virtualization.
  *
- *      (*) Under KVM, the host SPRG1 is used to point to
- *      the current VCPU data structure
- *
  * 32-bit 8xx:
  *	- SPRG0 scratch for exception vectors
  *	- SPRG1 scratch for exception vectors