iio: mlx90614: Convert to common field_{get,prep}() helpers

Drop the driver-specific field_get() and field_prep() macros, in favor
of the globally available variants from <linux/bitfield.h>.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Crt Mori <cmo@melexis.com>
Signed-off-by: Yury Norov (NVIDIA) <yury.norov@gmail.com>

drivers/iio/temperature/mlx90614.c

@@ -22,6 +22,7 @@
  * the "wakeup" GPIO is not given, power management will be disabled.
  */
 
+#include <linux/bitfield.h>
 #include <linux/delay.h>
 #include <linux/err.h>
 #include <linux/gpio/consumer.h>
@@ -68,12 +69,6 @@
 #define MLX90614_CONST_SCALE 20 /* Scale in milliKelvin (0.02 * 1000) */
 #define MLX90614_CONST_FIR 0x7 /* Fixed value for FIR part of low pass filter */
 
-/* Non-constant mask variant of FIELD_GET() and FIELD_PREP() */
-#undef field_get
-#define field_get(_mask, _reg)	(((_reg) & (_mask)) >> (ffs(_mask) - 1))
-#undef field_prep
-#define field_prep(_mask, _val)	(((_val) << (ffs(_mask) - 1)) & (_mask))
-
 struct mlx_chip_info {
 	/* EEPROM offsets with 16-bit data, MSB first */
 	/* emissivity correction coefficient */