dt-bindings: qcom_nandc: IPQ4019 QPIC NAND documentation

1. Qualcom IPQ4019 SoC uses QPIC NAND controller version 1.4.0
   which uses BAM DMA Engine while IPQ806x uses EBI2 NAND
   which uses ADM DMA Engine.
2. QPIC NAND will 3 BAM channels: command, data tx and data rx
   while EBI2 NAND uses only single ADM channel.
3. CRCI is only required for ADM DMA and its not required for
   BAM DMA.

Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Abhishek Sahu <absahu@codeaurora.org>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>