staging: rtl8723au: hal: Use 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/rtl8723au/hal/usb_halinit.c

@@ -736,8 +736,7 @@ int rtl8723au_hal_init(struct rtw_adapter *Adapter)
 
 	rtl8723a_InitHalDm(Adapter);
 
-	val8 = (WiFiNavUpperUs + HAL_8723A_NAV_UPPER_UNIT - 1) /
-		HAL_8723A_NAV_UPPER_UNIT;
+	val8 = DIV_ROUND_UP(WiFiNavUpperUs, HAL_8723A_NAV_UPPER_UNIT);
 	rtl8723au_write8(Adapter, REG_NAV_UPPER, val8);
 
 	/*  2011/03/09 MH debug only, UMC-B cut pass 2500 S5 test, but we need to fin root cause. */