mtd: rawnand: brcmnand: Add support for v7.3 controller

This change adds support for brcm NAND v7.3 controller. This controller
uses a newer version of flash_dma engine and change mostly implements
these differences.

Signed-off-by: Kamal Dasu <kdasu.kdev@gmail.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>