ioping: print at least three decimal digits

This prints two digits after decimal point if value lower than ten and
dosn't print decimal point at all if unit exactly fits to the value.
Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com>

ioping.c

@@ -24,7 +24,6 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdarg.h>
-#include <inttypes.h>
 #include <getopt.h>
 #include <string.h>
 #include <unistd.h>
@@ -353,12 +352,19 @@ long long parse_time(const char *str)
 
 void print_suffix(int64_t val, struct suffix *sfx)
 {
+	int precision;
+
 	while (val < sfx->mul && sfx->mul > 1)
 		sfx++;
-	if (sfx->mul == 1)
-		printf("%" PRId64, val);
+
+	if (val % sfx->mul == 0)
+		precision = 0;
+	else if (val >= sfx->mul * 10)
+		precision = 1;
 	else
-		printf("%.1f", val * 1.0 / sfx->mul);
+		precision = 2;
+
+	printf("%.*f", precision, val * 1.0 / sfx->mul);
 	if (*sfx->txt)
 		printf(" %s", sfx->txt);
 }