spi: spi-fsl-dspi: Convert the instantiations that support it to DMA

The A-011218 eDMA/DSPI erratum affects most of the older Layerscape SoCs
with DSPI, and its workaround is a bit intrusive.

After this patch, there are no users of TCFQ mode that don't also
support XSPI (previously there was LS2085A).

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Message-Id: <20200302001958.11105-7-olteanv@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>