[ALSA] Define MPU401 registers in sound/mpu401_uart.h

Define some MPU401 registers in sound/mpu401_uart.h so that other
drivers can refer to them.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/drivers/mpu401/mpu401_uart.c b/sound/drivers/mpu401/mpu401_uart.c
index dd6ec42..18cca24 100644
--- a/sound/drivers/mpu401/mpu401_uart.c
+++ b/sound/drivers/mpu401/mpu401_uart.c
@@ -49,12 +49,10 @@
 
  */
 
-#define snd_mpu401_input_avail(mpu)	(!(mpu->read(mpu, MPU401C(mpu)) & 0x80))
-#define snd_mpu401_output_ready(mpu)	(!(mpu->read(mpu, MPU401C(mpu)) & 0x40))
-
-#define MPU401_RESET		0xff
-#define MPU401_ENTER_UART	0x3f
-#define MPU401_ACK		0xfe
+#define snd_mpu401_input_avail(mpu) \
+	(!(mpu->read(mpu, MPU401C(mpu)) & MPU401_RX_EMPTY))
+#define snd_mpu401_output_ready(mpu) \
+	(!(mpu->read(mpu, MPU401C(mpu)) & MPU401_TX_FULL))
 
 /* Build in lowlevel io */
 static void mpu401_write_port(struct snd_mpu401 *mpu, unsigned char data,