iio: tsl2583: Use DIV_ROUND_CLOSEST() instead of open-coding it

Use DIV_ROUND_CLOSEST() instead of open-coding it. This documents intent
and makes it more clear what is going on for the casual reviewer.

Generated using the following the Coccinelle semantic patch.

// <smpl>
@r1@
expression x;
constant C1;
constant C2;
@@
 ((x) + C1) / C2

@script:python@
C1 << r1.C1;
C2 << r1.C2;
@@
try:
	if int(C1) * 2 != int(C2):
		cocci.include_match(False)
except:
	cocci.include_match(False)

@@
expression r1.x;
constant r1.C1;
constant r1.C2;
@@
-(((x) + C1) / C2)
+DIV_ROUND_CLOSEST(x, C2)
// </smpl>
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Link: https://lore.kernel.org/r/20201227171126.28216-3-lars@metafoo.deSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/light/tsl2583.c

@@ -285,7 +285,7 @@ static int tsl2583_get_lux(struct iio_dev *indio_dev)
 	lux64 = lux64 * chip->als_settings.als_gain_trim;
 	lux64 >>= 13;
 	lux = lux64;
-	lux = (lux + 500) / 1000;
+	lux = DIV_ROUND_CLOSEST(lux, 1000);
 
 	if (lux > TSL2583_LUX_CALC_OVER_FLOW) { /* check for overflow */
 return_max:
@@ -361,12 +361,12 @@ static int tsl2583_set_als_time(struct tsl2583_chip *chip)
 	u8 val;
 
 	/* determine als integration register */
-	als_count = (chip->als_settings.als_time * 100 + 135) / 270;
+	als_count = DIV_ROUND_CLOSEST(chip->als_settings.als_time * 100, 270);
 	if (!als_count)
 		als_count = 1; /* ensure at least one cycle */
 
 	/* convert back to time (encompasses overrides) */
-	als_time = (als_count * 27 + 5) / 10;
+	als_time = DIV_ROUND_CLOSEST(als_count * 27, 10);
 
 	val = 256 - als_count;
 	ret = i2c_smbus_write_byte_data(chip->client,
@@ -380,7 +380,7 @@ static int tsl2583_set_als_time(struct tsl2583_chip *chip)
 
 	/* set chip struct re scaling and saturation */
 	chip->als_saturation = als_count * 922; /* 90% of full scale */
-	chip->als_time_scale = (als_time + 25) / 50;
+	chip->als_time_scale = DIV_ROUND_CLOSEST(als_time, 50);
 
 	return ret;
 }