spi: cadence-quadspi: Add compatible for AMD Pensando Elba SoC

The AMD Pensando Elba SoC has the Cadence QSPI controller integrated.

The quirk CQSPI_NEEDS_APB_AHB_HAZARD_WAR is added and if enabled
a dummy readback from the controller is performed to ensure
synchronization.

Signed-off-by: Brad Larson <blarson@amd.com>
Link: https://lore.kernel.org/r/20230515181606.65953-8-blarson@amd.com


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