[llvm] MC,AMDGPU: Don't pad .text with s_code_end if it would otherwise be empty (PR #147980)

[Tim Renouf via llvm-commits]

================
@@ -342,12 +342,10 @@ void MCObjectStreamer::emitInstructionImpl(const MCInst &Inst,
                                            const MCSubtargetInfo &STI) {
   MCStreamer::emitInstruction(Inst, STI);
 
-  MCSection *Sec = getCurrentSectionOnly();
----------------
trenouf wrote:

Fixed as suggested.

https://github.com/llvm/llvm-project/pull/147980