net: openvswitch: use div_u64() for 64-by-32 divisions

Compile the kernel for arm 32 platform, the build warning found.
To fix that, should use div_u64() for divisions.
| net/openvswitch/meter.c:396: undefined reference to `__udivdi3'

[add more commit msg, change reported tag, and use div_u64 instead
of do_div by Tonghao]

Fixes: e5735887 ("net: openvswitch: use u64 for meter bucket")
Reported-by: Nkbuild test robot <lkp@intel.com>
Signed-off-by: NTonghao Zhang <xiangxia.m.yue@gmail.com>
Tested-by: NTonghao Zhang <xiangxia.m.yue@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/openvswitch/meter.c

@@ -393,7 +393,7 @@ static struct dp_meter *dp_meter_create(struct nlattr **a)
 		 * Start with a full bucket.
 		 */
 		band->bucket = (band->burst_size + band->rate) * 1000ULL;
-		band_max_delta_t = band->bucket / band->rate;
+		band_max_delta_t = div_u64(band->bucket, band->rate);
 		if (band_max_delta_t > meter->max_delta_t)
 			meter->max_delta_t = band_max_delta_t;
 		band++;