The QPIC NAND BAM has multiple flags to control the transfer. This
patch adds flags parameter in register and data transfer DMA helper
functions and modifies all these functions call with appropriate
flags using following rule

1. Read and write can’t go in single command descriptor so
   separate SGL should be used.
2. For some of the requests, NWD flag should be set in BAM
   DMA descriptor.
3. For Data write, the BAM has internal buffer for each codeword.
   All write request will modify the data in internal buffer and
   this buffer will be flushed to NAND device once EOT flag is set.
   So for all the write requests in single codeword, the EOT should
   be cleared for all tx data descriptors except the last one.
Reviewed-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Abhishek Sahu <absahu@codeaurora.org>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>