iio:light:cm3323: make use of GENMASK

Use GENMASK to define the integration time bitmask.

Signed-off-by: Hartmut Knaack <knaack.h@gmx.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
diff --git a/drivers/iio/light/cm3323.c b/drivers/iio/light/cm3323.c
index af1b1b0..57ff0a1 100644
--- a/drivers/iio/light/cm3323.c
+++ b/drivers/iio/light/cm3323.c
@@ -29,7 +29,7 @@
 
 #define CM3323_CONF_SD_BIT	BIT(0) /* sensor disable */
 #define CM3323_CONF_AF_BIT	BIT(1) /* auto/manual force mode */
-#define CM3323_CONF_IT_MASK	(BIT(4) | BIT(5) | BIT(6))
+#define CM3323_CONF_IT_MASK	GENMASK(6, 4)
 #define CM3323_CONF_IT_SHIFT	4
 
 #define CM3323_INT_TIME_AVAILABLE "0.04 0.08 0.16 0.32 0.64 1.28"