Merge changes from topic "brcm_initial_support" into integration

* changes:
  doc: brcm: Add documentation file for brcm stingray platform
  drivers: Add SPI Nor flash support
  drivers: Add iproc spi driver
  drivers: Add emmc driver for Broadcom platforms
  Add BL31 support for Broadcom stingray platform
  Add BL2 support for Broadcom stingray platform
  Add bl31 support common across Broadcom platforms
  Add bl2 setup code common across Broadcom platforms
  drivers: Add support to retrieve plat_toc_flags