gem5: update to 9048ef0ffbf21bedb803b785fb68f83e95c04db8

--generate-dtb was removed and is set by default now

run

@@ -374,10 +374,7 @@ Run QEMU with VNC instead of the default SDL. Connect to it with:
                             dtb = self.env['dtb']
                         elif self.env['dp650']:
                             dtb = os.path.join(self.env['gem5_system_dir'], 'arm', 'dt', 'armv{}_gem5_v1_{}{}cpu.dtb'.format(self.env['armv'], dp650_cmd, self.env['cpus']))
-                        if dtb is None:
-                            if not self.env['baremetal']:
-                                cmd.extend(['--generate-dtb', LF])
-                        else:
+                        if dtb is not None:
                             cmd.extend(['--dtb-filename', dtb, LF])
                         if self.env['baremetal'] is None:
                             cmd.extend(['--param', 'system.panic_on_panic = True', LF ])