Merge changes from topic "static_analysis" into integration

* changes:
  io: io_stm32image: correct possible NULL pointer dereference
  plat/st: correctly check pwr-regulators node
  nand: stm32_fmc2_nand: correct xor_ecc.val assigned value
  plat/st: correct static analysis tool warning
  raw_nand: correct static analysis tool warning
  spi: stm32_qspi: correct static analysis issues