QSystemLocale: Fix the time format on BlackBerry 10

The time format should depend on the device settings (24 hour format)

cherry picked from qtbase/686c94c892006a3e72291ca8971aabf18ea1ec85

Change-Id: I6226486ee1feedc27fab49802a0043619e83659c
Reviewed-by: Rafael Roquetto <rafael.roquetto@kdab.com>