iio: max44000: correct value in illuminance_integration_time_available

According to the datasheet, the shortest available integration time for
ALS ADC conversion is 1.5625ms but illuminance_integration_time_available
sysfs file shows wrong value.

Cc: Crestez Dan Leonard <leonard.crestez@intel.com>
Cc: Jonathan Cameron <jic23@kernel.org>
Cc: Hartmut Knaack <knaack.h@gmx.de>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Peter Meerwald-Stadler <pmeerw@pmeerw.net>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Fixes: d5d8f49 ("max44000: Expose ambient sensor scaling")
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/iio/light/max44000.c

@@ -113,7 +113,7 @@ static const char max44000_int_time_avail_str[] =
 	"0.100 "
 	"0.025 "
 	"0.00625 "
-	"0.001625";
+	"0.0015625";
 
 /* Available scales (internal to ulux) with pretty manual alignment: */
 static const int max44000_scale_avail_ulux_array[] = {