dt-bindings: fsi: Remove ibm,fsi2spi-restricted compatible

Remove this compatible string from the FSI SPI controller
documentation, since the security restrictions have been
universally applied to the controllers.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Link: https://lore.kernel.org/r/20210716133915.14697-3-eajames@linux.ibm.com


Signed-off-by: Mark Brown <broonie@kernel.org>