[ALSA] oxygen: save register writes

Save the written values of all CMI8788 and AC97 registers and of some of
the DAC/ADC registers so that it is possible to restore the register
state later.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>
diff --git a/sound/pci/oxygen/oxygen.h b/sound/pci/oxygen/oxygen.h
index 6c6efed..29c9fa4 100644
--- a/sound/pci/oxygen/oxygen.h
+++ b/sound/pci/oxygen/oxygen.h
@@ -80,6 +80,12 @@
 	struct work_struct spdif_input_bits_work;
 	struct work_struct gpio_work;
 	wait_queue_head_t ac97_waitqueue;
+	union {
+		u8 _8[OXYGEN_IO_SIZE];
+		__le16 _16[OXYGEN_IO_SIZE / 2];
+		__le32 _32[OXYGEN_IO_SIZE / 4];
+	} saved_registers;
+	u16 saved_ac97_registers[2][0x40];
 };
 
 struct oxygen_model {