Merge remote-tracking branches 'spi/topic/atmel', 'spi/topic/bcm2385',...

Merge remote-tracking branches 'spi/topic/atmel', 'spi/topic/bcm2385', 'spi/topic/bcm2835', 'spi/topic/bcm53xx' and 'spi/topic/bitbang' into spi-next