mtd: rawnand: denali: remove unused dma_addr field from denali_nand_info

This is a leftover of commit 997cde2a ("mtd: nand: denali: skip
driver internal bounce buffer when possible").

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>