ALSA: oss: 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>
@@
expression x, y;
@@
-((x) + ((y) / 2)) / (y)
+DIV_ROUND_CLOSEST(x, y)
// </smpl>

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Link: https://lore.kernel.org/r/20201223172229.781-13-lars@metafoo.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/core/oss/mixer_oss.c

@@ -418,7 +418,7 @@ static long snd_mixer_oss_conv(long val, long omin, long omax, long nmin, long n
 	
 	if (orange == 0)
 		return 0;
-	return ((nrange * (val - omin)) + (orange / 2)) / orange + nmin;
+	return DIV_ROUND_CLOSEST(nrange * (val - omin), orange) + nmin;
 }
 
 /* convert from alsa native to oss values (0-100) */

sound/core/oss/rate.c

@@ -193,7 +193,7 @@ static snd_pcm_sframes_t rate_src_frames(struct snd_pcm_plugin *plugin, snd_pcm_
 	if (plugin->src_format.rate < plugin->dst_format.rate) {
 		res = (((frames * data->pitch) + (BITS/2)) >> SHIFT);
 	} else {
-		res = (((frames << SHIFT) + (data->pitch / 2)) / data->pitch);		
+		res = DIV_ROUND_CLOSEST(frames << SHIFT, data->pitch);
 	}
 	if (data->old_src_frames > 0) {
 		snd_pcm_sframes_t frames1 = frames, res1 = data->old_dst_frames;
@@ -224,7 +224,7 @@ static snd_pcm_sframes_t rate_dst_frames(struct snd_pcm_plugin *plugin, snd_pcm_
 		return 0;
 	data = (struct rate_priv *)plugin->extra_data;
 	if (plugin->src_format.rate < plugin->dst_format.rate) {
-		res = (((frames << SHIFT) + (data->pitch / 2)) / data->pitch);
+		res = DIV_ROUND_CLOSEST(frames << SHIFT, data->pitch);
 	} else {
 		res = (((frames * data->pitch) + (BITS/2)) >> SHIFT);
 	}