sound: oxygen: allow custom MCLK rates

Add a callback that allows model drivers to modify the default I2S MCLK
rate.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/pci/oxygen/hifier.c b/sound/pci/oxygen/hifier.c
index 2079c10..e3c229b 100644
--- a/sound/pci/oxygen/hifier.c
+++ b/sound/pci/oxygen/hifier.c
@@ -170,6 +170,7 @@
 	.init = hifier_init,
 	.cleanup = hifier_cleanup,
 	.resume = hifier_resume,
+	.get_i2s_mclk = oxygen_default_i2s_mclk,
 	.set_dac_params = set_ak4396_params,
 	.set_adc_params = set_cs5340_params,
 	.update_dac_volume = update_ak4396_volume,