Merge changes from topic "fdt_wrappers_rework" into integration

* changes:
  arm: fconf: Fix GICv3 dynamic configuration
  plat/stm32: Implement fdt_read_uint32_default() as a wrapper
  fdt/wrappers: Replace fdtw_read_cells() implementation
  plat/stm32: Use generic fdt_read_uint32_array() implementation
  fdt/wrappers: Generalise fdtw_read_array()