Added new chThdDoDequeueNextI() API.

git-svn-id: svn://svn.code.sf.net/p/chibios/svn/trunk@7286 35acf78f-673a-0410-8e92-d51de3d6d3f4
Merge branch 'master' of https://github.com/ChibiOS-Upstream/ChibiOS-RT