mtd: spinand: winbond: Enable high-speed modes on w35n0xjw

w35n0xjw chips can run at up to 166MHz in octal mode, but this is only
possible after programming various VCR registers.

Implement the new ->configure_chip() hook for this purpose.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>