spi: bcm63xx-hsspi: Disable spi mem dual io read op support

In general the controller supports SPI dual mode operation but the
particular SPI flash dual io read op switches from single mode in cmd
phase to dual mode in address and data phase. This is not compatible
with prepend operation where cmd and address are sent out through the
prepend buffer and they must use same the number of io pins.

This patch disables these SPI flash dual io read ops through the mem_ops
supports_op interface. This makes sure the SPI flash driver selects the
compatible read ops at run time.

Signed-off-by: William Zhang <william.zhang@broadcom.com>
Link: https://lore.kernel.org/r/20230209200246.141520-14-william.zhang@broadcom.com


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