Updated SPI Makefile and Kconfig in order to contain the option
to compile am335x beaglebone black omap4 spi real-time driver.
Signed-off-by: Laurentiu-Cristian Duca <laurentiu.duca@gmail.com>
[Jan: enabled in CI build]
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>