ALSA: bt87x: Use DIV_ROUND_UP() instead of open-coding it

Use DIV_ROUND_UP() 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) != int(C2) - 1:
		cocci.include_match(False)
except:
	cocci.include_match(False)

@@
expression r1.x;
constant r1.C1;
constant r1.C2;
@@
-(((x) + C1) / C2)
+DIV_ROUND_UP(x, C2)
// </smpl>
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Link: https://lore.kernel.org/r/20201223172229.781-4-lars@metafoo.deSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/bt87x.c

@@ -327,7 +327,8 @@ static irqreturn_t snd_bt87x_interrupt(int irq, void *dev_id)
 		current_block = chip->current_line * 16 / chip->lines;
 		irq_block = status >> INT_RISCS_SHIFT;
 		if (current_block != irq_block)
-			chip->current_line = (irq_block * chip->lines + 15) / 16;
+			chip->current_line = DIV_ROUND_UP(irq_block * chip->lines,
+							  16);
 
 		snd_pcm_period_elapsed(chip->substream);
 	}