Staging: iio: cdc: Remove unused macros

Remove the macros since they are not used anywhere throughout the
kernel.
Signed-off-by: NShraddha Barke <shraddha.6596@gmail.com>
Reviewed-by: NDaniel Baluta <daniel.baluta@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/iio/cdc/ad7746.c

@@ -27,11 +27,7 @@
 
 #define AD7746_REG_STATUS		0
 #define AD7746_REG_CAP_DATA_HIGH	1
-#define AD7746_REG_CAP_DATA_MID		2
-#define AD7746_REG_CAP_DATA_LOW		3
 #define AD7746_REG_VT_DATA_HIGH		4
-#define AD7746_REG_VT_DATA_MID		5
-#define AD7746_REG_VT_DATA_LOW		6
 #define AD7746_REG_CAP_SETUP		7
 #define AD7746_REG_VT_SETUP		8
 #define AD7746_REG_EXC_SETUP		9
@@ -39,11 +35,8 @@
 #define AD7746_REG_CAPDACA		11
 #define AD7746_REG_CAPDACB		12
 #define AD7746_REG_CAP_OFFH		13
-#define AD7746_REG_CAP_OFFL		14
 #define AD7746_REG_CAP_GAINH		15
-#define AD7746_REG_CAP_GAINL		16
 #define AD7746_REG_VOLT_GAINH		17
-#define AD7746_REG_VOLT_GAINL		18
 
 /* Status Register Bit Designations (AD7746_REG_STATUS) */
 #define AD7746_STATUS_EXCERR		BIT(3)