spidev: introduce trivial abb sensor device

Merge series from Heiko Schocher <hs@denx.de>:

This series introduces the changes needed for trivial spi
based sensors from ABB, currently operated from userspace.

diff --cc MAINTAINERS
Simple merge

diff --cc drivers/spi/spi-cadence-quadspi.c
Simple merge

diff --cc drivers/spi/spi-fsl-dspi.c
Simple merge

diff --cc drivers/spi/spi-qpic-snand.c
Simple merge

diff --cc drivers/spi/spi.c
Simple merge

diff --cc include/linux/mtd/nand-qpic-common.h
Simple merge