mtd: rawnand: hynix: Implement ->choose_interface_config() for H27UCG8T2ATR-BC

This chip supports ONFI SDR timing mode 4, implement the new hook to
advertize it.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20200529111322.7184-26-miquel.raynal@bootlin.com