staging: comedi: ni_pcidio.c: Prefer using macro DIV_ROUND_UP

The macro DIV_ROUND_UP performs the computation
(((n) + (d) - 1) /(d)). It clarifies the divisor calculations.
This was done using the coccinelle script:
@@
expression e1;
expression e2;
@@
(
- ((e1) + e2 - 1) / (e2)
+ DIV_ROUND_UP(e1,e2)
|
- ((e1) + (e2 - 1)) / (e2)
+ DIV_ROUND_UP(e1,e2)
)

Signed-off-by: Bhaktipriya Shridhar <bhaktipriya96@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/drivers/ni_pcidio.c

@@ -531,7 +531,7 @@ static int ni_pcidio_ns_to_timer(int *nanosec, unsigned int flags)
 		divider = (*nanosec) / base;
 		break;
 	case CMDF_ROUND_UP:
-		divider = (*nanosec + base - 1) / base;
+		divider = DIV_ROUND_UP(*nanosec, base);
 		break;
 	}