Merge changes from topic "os/bl31-fpga-port" into integration

Merge changes from topic "os/bl31-fpga-port" into integration

* changes:
  plat/arm/board/arm_fpga: Compile with additional CPU libraries
  plat/arm/board/arm_fpga: Enable position-independent execution
  plat/arm/board/arm_fpga: Enable port for alternative cluster configurations
  plat/arm/board/arm_fpga: Initialize the Generic Interrupt Controller
  plat/arm/board/arm_fpga: Initialize the System Counter
  plat/arm/board/arm_fpga: Add PSCI implementation for FPGA images
  plat/arm/board/arm_fpga: Use preloaded BL33 alternative boot flow
  plat/arm/board/arm_fpga: Enable basic BL31 port for an FPGA image