spi: cadence: set cqspi to the driver_data field of struct device

When initialize cadence qspi controller, it is need to set cqspi
to the driver_data field of struct device, because it will be
used in function cqspi_remove/suspend/resume(). Otherwise, there
will be a crash trace as below when invoking these finctions.

Fixes: 31fb632b

 ("spi: Move cadence-quadspi driver to drivers/spi/")
Cc: stable@vger.kernel.org
Signed-off-by: Meng Li <Meng.Li@windriver.com>
Link: https://lore.kernel.org/r/20210311091220.3615-1-Meng.Li@windriver.com
Signed-off-by: Mark Brown <broonie@kernel.org>