spi: imx: issues with imx53-ecspi configuration

[André Pribil <a.pribil@xxxxxxxxxxxx>]

Hi,

as far as I see the imx53-ecspi configuration has been introduced 
to the spi imx driver to address some specific problems in the 
SPI controllers of the i.mx53 and the i.mx6 family.

>From my point of view the following issues exist with this 
configuration in the current driver version:

- The device trees for the i.mx6 family still use the imx51-ecspi 
  configuration and not the imx53-ecspi, where these issues are
  addressed.
- When looking into the NXP errata sheet for the i.mx51, the 
  "Burst completion by SS signal in slave mode" issue seems
  to be present here too. So why is this issue only fixed for
  the imx53-ecspi config? Or why do we need the imx53-ecspi config
  at all?
- When using the imx53-ecspi config, the driver outputs the 
  following message: "No setup_wml()?". The reason for this seems
  to be that the setup_wml() function was only added for the 
  imx51-ecspi config. It is missing in the imx53-ecspi config.
- The initialization of the "dynamic_burst" property is missing 
  for the imx53-ecspi config.

Best regards,
André