[SPARC64]: Do not write garbage into %pstate in tsb_context_switch().

For SUN4V, we were clobbering %o5 to do the hypervisor call.
This clobbers the saved %pstate value and we end up writing
garbage into that register as a result.  Oops.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

arch/sparc64/kernel/tsb.S

@@ -265,13 +265,19 @@ __tsb_context_switch:
 	mov	SCRATCHPAD_UTSBREG2, %g1
 	stxa	%g2, [%g1] ASI_SCRATCHPAD
 
+	/* Save away %o5's %pstate, we have to use %o5 for
+	 * the hypervisor call.
+	 */
+	mov	%o5, %g1
+
 	mov	HV_FAST_MMU_TSB_CTXNON0, %o5
 	mov	1, %o0
 	mov	%o4, %o1
 	ta	HV_FAST_TRAP
 
+	/* Finish up and restore %o5.  */
 	ba,pt	%xcc, 9f
-	 nop
+	 mov	%g1, %o5
 
 	/* SUN4U TSB switch.  */
 1:	mov	TSB_REG, %g1