sparc64: Make lock backoff really a NOP on UP builds.

As noticed by Mikulas Patocka, the backoff macros don't
completely nop out for UP builds, we still get a
branch always and a delay slot nop.

Fix this by making the branch to the backoff spin loop
selective, then we can nop out the spin loop completely.

Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/arch/sparc/lib/atomic_64.S b/arch/sparc/lib/atomic_64.S
index 703c9c3..59186e0 100644
--- a/arch/sparc/lib/atomic_64.S
+++ b/arch/sparc/lib/atomic_64.S
@@ -21,7 +21,7 @@
 	add	%g1, %o0, %g7
 	cas	[%o1], %g1, %g7
 	cmp	%g1, %g7
-	bne,pn	%icc, 2f
+	bne,pn	%icc, BACKOFF_LABEL(2f, 1b)
 	 nop
 	retl
 	 nop
@@ -36,7 +36,7 @@
 	sub	%g1, %o0, %g7
 	cas	[%o1], %g1, %g7
 	cmp	%g1, %g7
-	bne,pn	%icc, 2f
+	bne,pn	%icc, BACKOFF_LABEL(2f, 1b)
 	 nop
 	retl
 	 nop
@@ -51,7 +51,7 @@
 	add	%g1, %o0, %g7
 	cas	[%o1], %g1, %g7
 	cmp	%g1, %g7
-	bne,pn	%icc, 2f
+	bne,pn	%icc, BACKOFF_LABEL(2f, 1b)
 	 add	%g1, %o0, %g1
 	retl
 	 sra	%g1, 0, %o0
@@ -66,7 +66,7 @@
 	sub	%g1, %o0, %g7
 	cas	[%o1], %g1, %g7
 	cmp	%g1, %g7
-	bne,pn	%icc, 2f
+	bne,pn	%icc, BACKOFF_LABEL(2f, 1b)
 	 sub	%g1, %o0, %g1
 	retl
 	 sra	%g1, 0, %o0
@@ -81,7 +81,7 @@
 	add	%g1, %o0, %g7
 	casx	[%o1], %g1, %g7
 	cmp	%g1, %g7
-	bne,pn	%xcc, 2f
+	bne,pn	%xcc, BACKOFF_LABEL(2f, 1b)
 	 nop
 	retl
 	 nop
@@ -96,7 +96,7 @@
 	sub	%g1, %o0, %g7
 	casx	[%o1], %g1, %g7
 	cmp	%g1, %g7
-	bne,pn	%xcc, 2f
+	bne,pn	%xcc, BACKOFF_LABEL(2f, 1b)
 	 nop
 	retl
 	 nop
@@ -111,7 +111,7 @@
 	add	%g1, %o0, %g7
 	casx	[%o1], %g1, %g7
 	cmp	%g1, %g7
-	bne,pn	%xcc, 2f
+	bne,pn	%xcc, BACKOFF_LABEL(2f, 1b)
 	 nop
 	retl
 	 add	%g1, %o0, %o0
@@ -126,7 +126,7 @@
 	sub	%g1, %o0, %g7
 	casx	[%o1], %g1, %g7
 	cmp	%g1, %g7
-	bne,pn	%xcc, 2f
+	bne,pn	%xcc, BACKOFF_LABEL(2f, 1b)
 	 nop
 	retl
 	 sub	%g1, %o0, %o0