[KINETIS] Add support for FEI mode

git-svn-id: svn://svn.code.sf.net/p/chibios/svn/trunk@7178 35acf78f-673a-0410-8e92-d51de3d6d3f4
[KINETIS] Config option for FEI mode + PEE config moved

git-svn-id: svn://svn.code.sf.net/p/chibios/svn/trunk@7179 35acf78f-673a-0410-8e92-d51de3d6d3f4
[KINETIS] Fix typos and comments

git-svn-id: svn://svn.code.sf.net/p/chibios/svn/trunk@7180 35acf78f-673a-0410-8e92-d51de3d6d3f4