mtd: spi-nor: spansion: Rework spi_nor_cypress_octal_dtr_enable()

Introduce template operation to remove code duplication.
Split spi_nor_cypress_octal_dtr_enable() in
spi_nor_cypress_octal_dtr_ena() spi_nor_cypress_octal_dtr_dis() as it no
longer made sense to try to keep everything alltogether: too many
"if (enable)" throughout the code, which made the code difficult to read.
Add debug messages in case spi_nor_read_id() fails.

Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Pratyush Yadav <p.yadav@ti.com>
Reviewed-by: Pratyush Yadav <p.yadav@ti.com>
Reviewed-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20220420103427.47867-9-tudor.ambarus@microchip.com