Give wider types to sscanf to fix two warnings (u_short cannot be > 0xffff)

and to make sure that we catch oversized arguments rather than silently
truncate them.  I dont know if sscanf will reject an integer if it will
not fit in the short return variable or not, but this way it should be
detected.

sbin/ifconfig/ifconfig.c

@@ -1687,9 +1687,9 @@ void
 setatrange(const char *range, int dummy __unused, int s, 
     const struct afswtch *afp)
 {
-	u_short	first = 123, last = 123;
+	u_int	first = 123, last = 123;
 
-	if (sscanf(range, "%hu-%hu", &first, &last) != 2
+	if (sscanf(range, "%u-%u", &first, &last) != 2
 	    || first == 0 || first > 0xffff
 	    || last == 0 || last > 0xffff || first > last)
 		errx(1, "%s: illegal net range: %u-%u", range, first, last);