In iostat(8) output, skip the decimal point and the fractional part

for tps >= 100 and MB/s >= 1000, to prevent them for widening too much.

MFC after:	2 weeks

usr.sbin/iostat/iostat.c

@@ -945,9 +945,11 @@ devstats(int perf_select, long double etime, int havelast)
 				       ms_per_transaction);
 		} else {
 			if (Iflag == 0)
-				printf(" %4.1Lf %4.0Lf %5.1Lf ",
+				printf(" %4.*Lf %4.0Lf %5.*Lf ",
+				       kb_per_transfer >= 100 ? 0 : 1,
 				       kb_per_transfer,
 				       transfers_per_second,
+				       mb_per_second >= 1000 ? 0 : 1,
 				       mb_per_second);
 			else {
 				total_mb = total_bytes;