Fix branch relaxation in 16-bit mode.

Thread through MCSubtargetInfo to relaxInstruction function allowing relaxation
to generate jumps with 16-bit sized immediates in 16-bit mode.

This fixes PR22097.

Reviewers: dwmw2, tstellarAMD, craig.topper, jyknight

Subscribers: jfb, arsenm, jyknight, llvm-commits, dsanders

Differential Revision: http://reviews.llvm.org/D20830

llvm-svn: 275068
diff --git a/llvm/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp b/llvm/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp
index 2f6a449..0fc7582 100644
--- a/llvm/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp
+++ b/llvm/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp
@@ -258,7 +258,9 @@
   return reasonForFixupRelaxation(Fixup, Value);
 }
 
-void ARMAsmBackend::relaxInstruction(const MCInst &Inst, MCInst &Res) const {
+void ARMAsmBackend::relaxInstruction(const MCInst &Inst,
+                                     const MCSubtargetInfo &STI,
+                                     MCInst &Res) const {
   unsigned RelaxedOp = getRelaxedOpcode(Inst.getOpcode());
 
   // Sanity check w/ diagnostic if we get here w/ a bogus instruction.