examples/performance-thread: remove unused hits count

Reported by clang 13.
This patch removes the hits variable from the cpu_load_collector function
within the performance thread example app as it is an unused but set
variable.

Bugzilla ID: 881
Fixes: d48415e ("examples/performance-thread: add l3fwd-thread app")
Cc: stable@dpdk.org

Reported-by: Liang Longfeng <longfengx.liang@intel.com>
Signed-off-by: Conor Walsh <conor.walsh@intel.com>
Reviewed-by: David Marchand <david.marchand@redhat.com>

examples/performance-thread/l3fwd-thread/main.c

@@ -1885,7 +1885,6 @@ process_burst(struct rte_mbuf *pkts_burst[MAX_PKT_BURST], int nb_rx,
 static int __rte_noreturn
 cpu_load_collector(__rte_unused void *arg) {
 	unsigned i, j, k;
-	uint64_t hits;
 	uint64_t prev_tsc, diff_tsc, cur_tsc;
 	uint64_t total[MAX_CPU] = { 0 };
 	unsigned min_cpu = MAX_CPU;
@@ -1972,12 +1971,10 @@ cpu_load_collector(__rte_unused void *arg) {
 			printf("cpu#     proc%%  poll%%  overhead%%\n\n");
 
 			for (i = min_cpu; i <= max_cpu; i++) {
-				hits = 0;
 				printf("CPU %d:", i);
 				for (j = 0; j < MAX_CPU_COUNTER; j++) {
 					printf("%7" PRIu64 "",
 							cpu_load.hits[j][i] * 100 / cpu_load.counter);
-					hits += cpu_load.hits[j][i];
 					cpu_load.hits[j][i] = 0;
 				}
 				printf("%7" PRIu64 "\n",