ALSA: hda: add register offset for stripe control

bits 16:17 in SD_CTL register refer to stripe control. Added an
offset register(AZX_REG_SD_CTL_3B) to have exclusive read/write
of corresponding register byte. This helps to avoid unnecessary
32-bit read/write of SD_CTL whenever only stripe or other bits of
corresponding byte need to be updated. Also HD audio spec defines
SD_CTL as 3 byte register.

SD_CTL_STRIPE_MASK(0x3) can be used for stripe control programming
and when updating AZX_REG_SD_CTL_3B.

Signed-off-by: Sameer Pujar <spujar@nvidia.com>
Reviewed-by: Mohan Kumar D <mkumard@nvidia.com>
Reviewed-by: Ravindra Lokhande <rlokhande@nvidia.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

include/sound/hda_register.h

@@ -79,6 +79,7 @@ enum { SDI0, SDI1, SDI2, SDI3, SDO0, SDO1, SDO2, SDO3 };
 
 /* stream register offsets from stream base */
 #define AZX_REG_SD_CTL			0x00
+#define AZX_REG_SD_CTL_3B		0x02 /* 3rd byte of SD_CTL register */
 #define AZX_REG_SD_STS			0x03
 #define AZX_REG_SD_LPIB			0x04
 #define AZX_REG_SD_CBL			0x08
@@ -165,6 +166,7 @@ enum { SDI0, SDI1, SDI2, SDI3, SDO0, SDO1, SDO2, SDO3 };
 #define SD_INT_COMPLETE		0x04	/* completion interrupt */
 #define SD_INT_MASK		(SD_INT_DESC_ERR|SD_INT_FIFO_ERR|\
 				 SD_INT_COMPLETE)
+#define SD_CTL_STRIPE_MASK	0x3	/* stripe control mask */
 
 /* SD_STS */
 #define SD_STS_FIFO_READY	0x20	/* FIFO ready */