gem5: fix trace file path on common

Author: cirosantilli

common

@@ -88,7 +88,7 @@ set_common_vars() {
   else
     common_run_dir="$common_qemu_run_dir"
   fi
-  common_trace_txt_file="${common_run_dir}/trace.txt"
+  common_trace_txt_file="${common_m5out_dir}/trace.txt"
   case "$arch" in
     arm)
       common_linux_image=arch/arm/boot/zImage