For now, enable the clrex instruction for armv6, until upstream
implements this properly.

Submitted by:	rdivacky

Introduced here: http://svnweb.freebsd.org/changeset/base/275362

Index: lib/Target/ARM/ARMInstrInfo.td
===================================================================
--- lib/Target/ARM/ARMInstrInfo.td
+++ lib/Target/ARM/ARMInstrInfo.td
@@ -4640,7 +4640,7 @@ def STLEXD : AIstlex<0b01, (outs GPR:$Rd),
 
 def CLREX : AXI<(outs), (ins), MiscFrm, NoItinerary, "clrex",
                 [(int_arm_clrex)]>,
-            Requires<[IsARM, HasV7]>  {
+            Requires<[IsARM, HasV6]>  {
   let Inst{31-0} = 0b11110101011111111111000000011111;
 }