[nrf fromtree] samples: zms: fix the loop_cnt iteration 0 check

- fix unwanted "Error: Something went wrong at iteration 0".
- the loop_cnt check has no sense for iteration 0,
  comparing with wrong -1.

Signed-off-by: Andrej Butok <[email protected]>
(cherry picked from commit 2766c78)

Author: butok

samples/subsys/fs/zms/src/main.c

@@ -161,7 +161,8 @@ int main(void)
 		rc = zms_read(&fs, CNT_ID, &i_cnt, sizeof(i_cnt));
 		if (rc > 0) { /* item was found, show it */
 			printk("Id: %d, loop_cnt: %u\n", CNT_ID, i_cnt);
-			if (i_cnt != (i - 1)) {
+			if ((i > 0) && (i_cnt != (i - 1))) {
+				printk("Error loop_cnt %u must be %d\n", i_cnt, i - 1);
 				break;
 			}
 		}