tools/xenalyze: Avoid redundant check

Coverity notices that if !head is true, that !N can never be true.

Don't bother checking N, since we know it has to be at least one.

CID 1354243

Signed-off-by: George Dunlap <george.dunlap@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>

tools/xentrace/xenalyze.c

@@ -4146,9 +4146,6 @@ void cr3_dump_list(struct cr3_value_struct *head){
     for(p=head; p; p=p->next)
         N++;
 
-    if(!N)
-        return;
-
     /* Alloc a struct of the right size */
     qsort_array = malloc(N * sizeof(struct eip_list_struct *));