[SPARC64]: Fix bogus flush instruction usage.

Some of the trap code was still assuming that alternate
global %g6 was hard coded with current_thread_info().
Let's just consistently flush at KERNBASE when we need
a pipeline synchronization.  That's locked into the TLB
and will always work.

Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/arch/sparc64/kernel/rtrap.S b/arch/sparc64/kernel/rtrap.S
index 5a62ec5..89794ebd 100644
--- a/arch/sparc64/kernel/rtrap.S
+++ b/arch/sparc64/kernel/rtrap.S
@@ -259,7 +259,8 @@
 		ldx			[%l1 + %lo(sparc64_kern_pri_nuc_bits)], %l1
 		or			%l0, %l1, %l0
 		stxa			%l0, [%l7] ASI_DMMU
-		flush			%g6
+		sethi			%hi(KERNBASE), %l7
+		flush			%l7
 		rdpr			%wstate, %l1
 		rdpr			%otherwin, %l2
 		srl			%l1, 3, %l1