spi: imx: add selection for iMX53 and iMX6 controller

ECSPI contorller for iMX53 and iMX6 has few hardware issues
comparing to iMX51.
The change add possibility to detect which controller is used
to apply possible workaround and limitations.

Signed-off-by: Jiada Wang <jiada_wang@mentor.com>
Acked-by: Rob Herring <robh@kernel.org>
Reviewed-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Mark Brown <broonie@kernel.org>