KVM: PPC: Book3S HV: Add register name when loading toc

Add 'r' to register name r2 in kvmppc_hv_enter.

Also update comment at the top of kvmppc_hv_enter to indicate that R2/TOC is
non-volatile.

Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>

arch/powerpc/kvm/book3s_hv_rmhandlers.S

@@ -355,6 +355,7 @@ kvmppc_hv_entry:
 	 * MSR = ~IR|DR
 	 * R13 = PACA
 	 * R1 = host R1
+	 * R2 = TOC
 	 * all other volatile GPRS = free
 	 */
 	mflr	r0
@@ -503,7 +504,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S)
 toc_tlbie_lock:
 	.tc	native_tlbie_lock[TC],native_tlbie_lock
 	.previous
-	ld	r3,toc_tlbie_lock@toc(2)
+	ld	r3,toc_tlbie_lock@toc(r2)
 #ifdef __BIG_ENDIAN__
 	lwz	r8,PACA_LOCK_TOKEN(r13)
 #else