In order to prepare driver for the extension to support newer hardware,
add 'mfld' suffix to some related functions.

While here, move DMA parameters assignment under existing #ifdef
CONFIG_SPI_DW_MID_DMA.

There is no functional change intended.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200506153025.21441-6-andriy.shevchenko@linux.intel.comSigned-off-by: Mark Brown <broonie@kernel.org>