mtd: rawnand: sunxi: Add A23/A33 DMA support with extra MBUS configuration

Allwinner NAND controllers can make use of DMA to enhance the I/O
throughput thanks to ECC pipelining. DMA handling with A23/A33 NAND IP
is a bit different than with the older SoCs, hence the introduction of
a new compatible to handle:
* the differences between register offsets,
* the burst length change from 4 to minimum 8,
* manage SRAM accesses through MBUS with extra configuration.

Fixes: c49836f0

 ("mtd: rawnand: sunxi: Add A23/A33 DMA support")
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>