As RPL Root, drop an incoming DIO from the same instance but different DAG
Merge pull request #406 from cetic/hotfix-rplroot-discard-dio

Drop incoming DIO when RPL Root
Merge pull request #413 from ADVANSEE/cc2538-build

cc2538: Various build improvements
Merge pull request #410 from ADVANSEE/cc2538-sys_ctrl

cc2538: sys_ctrl: Make it possible to use the 32-kHz crystal
Merge branch 'master' into qidevices

Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>