mtd: spi-nor: Move manufacturer quad_enable() in ->default_init()

The goal is to move the quad_enable manufacturer specific init in the
nor->manufacturer->fixups->default_init()

The legacy quad_enable() implementation is spansion_quad_enable(),
select this method by default.

Set specific manufacturer fixups->default_init() hooks to overwrite
the default quad_enable() implementation when needed.

Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Vignesh Raghavendra <vigneshr@ti.com>