altera-ps-spi loads FPGA firmware over SPI, using the "passive serial"
interface on Altera Arria 10, Cyclone V or Stratix V FPGAs.

This is one of the simpler ways to set up an FPGA at runtime.
The signal interface is close to unidirectional SPI with lsb first.
Signed-off-by: NJoshua Clayton <stillcompiling@gmail.com>
Signed-off-by: NAnatolij Gustschin <agust@denx.de>
Signed-off-by: NAlan Tull <atull@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>