Merge changes Ie6a13e4a,I517074b8,Ifd29b748,I1279d9cb,I3b78e0c5, ... into integration

* changes:
  feat(imx8mq): add BL31 PIE support
  refactor(imx8mq): introduce BL31_SIZE
  refactor(imx8mq): make use of setup_page_tables()
  feat(imx8mq): always set up console
  feat(imx8mq): remove empty bl31_plat_runtime_setup
  feat(imx8mq): make IMX_BOOT_UART_BASE configurable via build parameter