[KINETIS] DMA registers and fields.

git-svn-id: svn://svn.code.sf.net/p/chibios/svn/trunk@7299 35acf78f-673a-0410-8e92-d51de3d6d3f4
[KINETIS] K20x SPI converted to use DMA.

git-svn-id: svn://svn.code.sf.net/p/chibios/svn/trunk@7300 35acf78f-673a-0410-8e92-d51de3d6d3f4
[KINETIS] K20x SPI demo converted to use DMA.

git-svn-id: svn://svn.code.sf.net/p/chibios/svn/trunk@7301 35acf78f-673a-0410-8e92-d51de3d6d3f4