emit_glasm_context_get_set: Remove unused variable

src/shader_recompiler/backend/glasm/emit_glasm_context_get_set.cpp

@@ -20,7 +20,6 @@ void GetCbuf(EmitContext& ctx, IR::Inst& inst, const IR::Value& binding, ScalarU
     const Register ret{ctx.reg_alloc.Define(inst)};
     if (offset.type == Type::U32) {
         // Avoid reading arrays out of bounds, matching hardware's behavior
-        const u32 imm_offset{offset.imm_u32};
         if (offset.imm_u32 >= 0x10'000) {
             ctx.Add("MOV.S {},0;", ret);
             return;