ARM: socfpga: Add FPGA drivers for Arria 10 FPGA bitstream loading

Add FPGA driver to support program FPGA with FPGA bitstream loading from
filesystem. The driver are designed based on generic firmware loader
framework. The driver can handle FPGA program operation from loading FPGA
bitstream in flash to memory and then to program FPGA.

Signed-off-by: Tien Fong Chee <tien.fong.chee@intel.com>