spdk_top: fix format warning around `thread_info->core_num`

On `ncurses-6.3` format attributes now detect argument mismatch:

    spdk_top.c:2218:60: warning: format '%lu' expects argument of type 'long unsigned int', but argument 5 has type 'int' [-Wformat=]
     2218 |         mvwprintw(thread_win, 3, THREAD_WIN_FIRST_COL + 6, "%" PRIu64,
          |                                                            ^~~
     2219 |                   thread_info->core_num);
          |                   ~~~~~~~~~~~~~~~~~~~~~
          |                              int

Use '%d" for `thread_info->core_num` (declared as `int`).

Signed-off-by: Sergei Trofimovich <slyich@gmail.com>
Change-Id: I99cd4ff41a26917b67199ea8cc1fbf281ce4dd20
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/10375


Community-CI: Broadcom CI <spdk-ci.pdl@broadcom.com>
Community-CI: Mellanox Build Bot
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Tomasz Zawadzki <tomasz.zawadzki@intel.com>
Reviewed-by: John Kariuki <John.K.Kariuki@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>