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