Make FPGA specific settings configurable (padding, spi bits per word,
delays) and add Arria 10 support. The Arria 10 compatible is the same
as in the kernel patch "fpga manager: Add altera-ps-spi driver for
Altera FPGAs" (drivers/fpga/altera-ps-spi.c). The Arria 5 compatible
works unchanged.

This patch was tested with Arria 5 and Arria 10.

Signed-off-by: Bastian Stender <bst@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>