Fixed ARMv7 port code by backporting the files from 2.6.x branch.

git-svn-id: svn://svn.code.sf.net/p/chibios/svn/branches/stable_2.4.x@6559 35acf78f-673a-0410-8e92-d51de3d6d3f4
Fixed bugs #445 and #446.

git-svn-id: svn://svn.code.sf.net/p/chibios/svn/branches/stable_2.4.x@6561 35acf78f-673a-0410-8e92-d51de3d6d3f4
Merge branch 'stable_2.4.x' of ssh://git@github.com/brewbit/ChibiOS-RT.git into stable_2.4.x
Merge branch 'stable_2.4.x' of github.com:brewbit/ChibiOS-RT into stable_2.4.x