fbdev: use DIV_ROUND_UP or roundup

The kernel.h macro DIV_ROUND_UP performs the computation (((n) + (d) - 1) /
(d)) but is perhaps more readable.

An extract of the semantic patch that makes this change is as follows:
(http://www.emn.fr/x-info/coccinelle/)

// <smpl>
@haskernel@
@@

#include <linux/kernel.h>

@depends on haskernel@
expression n,d;
@@

(
- (n + d - 1) / d
+ DIV_ROUND_UP(n,d)
|
- (n + (d - 1)) / d
+ DIV_ROUND_UP(n,d)
)

@depends on haskernel@
expression n,d;
@@

- DIV_ROUND_UP((n),d)
+ DIV_ROUND_UP(n,d)

@depends on haskernel@
expression n,d;
@@

- DIV_ROUND_UP(n,(d))
+ DIV_ROUND_UP(n,d)
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/video/gxt4500.c b/drivers/video/gxt4500.c
index e92337b..5645577 100644
--- a/drivers/video/gxt4500.c
+++ b/drivers/video/gxt4500.c
@@ -238,7 +238,7 @@
 	for (pdiv1 = 1; pdiv1 <= 8; ++pdiv1) {
 		for (pdiv2 = 1; pdiv2 <= pdiv1; ++pdiv2) {
 			postdiv = pdiv1 * pdiv2;
-			pll_period = (period_ps + postdiv - 1) / postdiv;
+			pll_period = DIV_ROUND_UP(period_ps, postdiv);
 			/* keep pll in range 350..600 MHz */
 			if (pll_period < 1666 || pll_period > 2857)
 				continue;