examples/nvmf: modify help case to return 0

Case 'h' or 'H' should return 0, this is a normal return.

Change-Id: I33888fdd8f293b5a297a629a80cf925917b32df8
Signed-off-by: wanghailiangx <hailiangx.e.wang@intel.com>
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/6062
Community-CI: Broadcom CI
Community-CI: Mellanox Build Bot
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Ziye Yang <ziye.yang@intel.com>
Reviewed-by: Aleksey Marchuk <alexeymar@mellanox.com>
Reviewed-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Reviewed-by: Changpeng Liu <changpeng.liu@intel.com>

examples/nvmf/nvmf/nvmf.c

@@ -183,6 +183,8 @@ parse_args(int argc, char **argv, struct spdk_env_opts *opts)
 			opts->no_pci = true;
 			break;
 		case 'h':
+			usage(argv[0]);
+			exit(EXIT_SUCCESS);
 		default:
 			usage(argv[0]);
 			return 1;