mtd: spi-nor-core: Add support for Cypress Semper flash

The Cypress Semper flash is an xSPI compliant octal DTR flash. Add
support for using it in octal DTR mode.

The flash by default boots in a hybrid sector mode. Switch to uniform
sector mode on boot. Use the default 20 dummy cycles for a read fast
command.

The SFDP programming on some older versions of the flash was incorrect.
Fixes for that are included in the fixup hooks.

Signed-off-by: Pratyush Yadav <p.yadav@ti.com>
Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>