dmaengine: add a driver for AMBA AXI NBPF DMAC IP cores

This patch adds a driver for NBPF DMAC IP cores from Renesas, designed for
the AMBA AXI bus.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski+renesas@gmail.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

diff --cc drivers/dma/Kconfig
Simple merge

diff --cc drivers/dma/Makefile
Simple merge

diff --cc drivers/dma/nbpfaxi.c
Simple merge