[KINETIS] Add EXT driver

git-svn-id: svn://svn.code.sf.net/p/chibios/svn/trunk@7215 35acf78f-673a-0410-8e92-d51de3d6d3f4
[KINETIS] Move to standardized port skel

git-svn-id: svn://svn.code.sf.net/p/chibios/svn/trunk@7216 35acf78f-673a-0410-8e92-d51de3d6d3f4
[KINETIS] EXT demos

git-svn-id: svn://svn.code.sf.net/p/chibios/svn/trunk@7217 35acf78f-673a-0410-8e92-d51de3d6d3f4