mtd: rawnand: meson: refactor use of 'meson_nfc_cmd_access()'

Move call 'meson_nfc_cmd_seed()' and check for 'NAND_NEED_SCRAMBLING'
to 'meson_nfc_cmd_access()', thus removing code duplication.

Signed-off-by: Arseniy Krasnov <avkrasnov@salutedevices.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20240507230903.3399594-3-avkrasnov@salutedevices.com