spi: fsi: Remove multiple sequenced ops for restricted chips

Updated restricted chips have trouble processing multiple sequenced
operations. So remove the capability to sequence multiple operations and
reduce the maximum transfer size to 8 bytes.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Link: https://lore.kernel.org/r/20210324220516.41192-1-eajames@linux.ibm.com


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