ASoC: SOF: Fix unused variable warnings

The recent fix for the build fix caused a couple of unused variable
compiler warnings when CONFIG_SND_SOC_SOF_NOCODEC isn't set:
  sound/soc/sof/core.c:263:6: warning: unused variable ‘ret’ [-Wunused-variable]
  sound/soc/sof/core.c:262:28: warning: unused variable ‘machine’ [-Wunused-variable]

Fix them by adding another ifdef.

Fixes: ce38a750 ("ASoC: SOF: core: fix undefined nocodec reference")
Signed-off-by: NTakashi Iwai <tiwai@suse.de>
Signed-off-by: NMark Brown <broonie@kernel.org>

sound/soc/sof/core.c

@@ -259,8 +259,10 @@ int snd_sof_create_page_table(struct snd_sof_dev *sdev,
 static int sof_machine_check(struct snd_sof_dev *sdev)
 {
 	struct snd_sof_pdata *plat_data = sdev->pdata;
+#if IS_ENABLED(CONFIG_SND_SOC_SOF_NOCODEC)
 	struct snd_soc_acpi_mach *machine;
 	int ret;
+#endif
 
 	if (plat_data->machine)
 		return 0;