Fix overflow in time2tick / tick2time.

The helper functions gets passed an unsigned int, which gets cast to long
and overflows.

See Debian bug #175462 - http://bugs.debian.org/175462

Signed-off-by: Andreas Henriksson <andreas@fatal.se>

diff -uri iproute-20070313.orig/tc/tc_core.c iproute-20070313/tc/tc_core.c
--- iproute-20070313.orig/tc/tc_core.c	2007-03-13 22:50:56.000000000 +0100
+++ iproute-20070313/tc/tc_core.c	2007-08-15 00:41:30.000000000 +0200
@@ -35,12 +35,12 @@
 }
 
 
-long tc_core_time2tick(long time)
+unsigned tc_core_time2tick(unsigned time)
 {
 	return time*tick_in_usec;
 }
 
-long tc_core_tick2time(long tick)
+unsigned tc_core_tick2time(unsigned tick)
 {
 	return tick/tick_in_usec;
 }
diff -uri iproute-20070313.orig/tc/tc_core.h iproute-20070313/tc/tc_core.h
--- iproute-20070313.orig/tc/tc_core.h	2007-03-13 22:50:56.000000000 +0100
+++ iproute-20070313/tc/tc_core.h	2007-08-15 00:41:49.000000000 +0200
@@ -7,8 +7,8 @@
 #define TIME_UNITS_PER_SEC	1000000000
 
 int  tc_core_time2big(long time);
-long tc_core_time2tick(long time);
-long tc_core_tick2time(long tick);
+unsigned tc_core_time2tick(unsigned time);
+unsigned tc_core_tick2time(unsigned tick);
 long tc_core_time2ktime(long time);
 long tc_core_ktime2time(long ktime);
 unsigned tc_calc_xmittime(unsigned rate, unsigned size);