target-alpha: fix syscall error check

(re-add commit 5689)
Signed-off-by: NAurelien Jarno <aurelien@aurel32.net>

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5692 c046a42c-6fe2-441c-8c8c-71466251a162

hw/alpha_palcode.c

@@ -1059,7 +1059,7 @@ void pal_init (CPUState *env)
 
 void call_pal (CPUState *env, int palcode)
 {
-    target_ulong ret;
+    target_long ret;
 
     if (logfile != NULL)
         fprintf(logfile, "%s: palcode %02x\n", __func__, palcode);