iris: replace all dup() with os_dupfd_cloexec()

Signed-off-by: Eric Engestrom <eric@engestrom.ch>
Reviewed-by: Kristian H. Kristensen <hoegsberg@google.com>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5369>

src/gallium/drivers/iris/iris_bufmgr.c

@@ -1801,7 +1801,7 @@ iris_bufmgr_create(struct gen_device_info *devinfo, int fd, bool bo_reuse)
     * Don't do this! Ensure that each library/bufmgr has its own device
     * fd so that its namespace does not clash with another.
     */
-   bufmgr->fd = dup(fd);
+   bufmgr->fd = os_dupfd_cloexec(fd);
 
    p_atomic_set(&bufmgr->refcount, 1);