linux-atm: Fix compile warning

The function trace_on_exit() is given to atexit() as a parameter, but
atexit() only takes a function pointer to a function with a void
parameter.

This problem was introduced when the on_exit() function was incompletely
replaced by atexit().

Fixes: ba6c8bd614 ("linux-atm: add portability fixes")
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>

package/network/utils/linux-atm/patches/400-portability_fixes.patch

@@ -34,7 +34,21 @@
  #include <linux/atmioc.h>
 --- a/src/sigd/atmsigd.c
 +++ b/src/sigd/atmsigd.c
-@@ -517,7 +517,7 @@ int main(int argc,char **argv)
+@@ -283,12 +283,11 @@ static void setup_signals(void)
+ /* ------------------------------- main ...  ------------------------------- */
+ 
+ 
+-static void trace_on_exit(int status,void *dummy)
++static void trace_on_exit(void)
+ {
+     char path[PATH_MAX+1];
+     FILE *file;
+ 
+-    if (!status) return;
+     if (!dump_dir) file = stderr;
+     else {
+ 	sprintf(path,"atmsigd.%d.trace.exit",getpid());
+@@ -517,7 +516,7 @@ int main(int argc,char **argv)
  	    exit(0);
  	}
      }