update submodules

Signed-off-by: Ruben Smits <ruben.smits@intermodalics.eu>
update rtt

Signed-off-by: Ruben Smits <ruben.smits@intermodalics.eu>
update upstream

Signed-off-by: Ruben Smits <ruben.smits@intermodalics.eu>
new upstream version

Signed-off-by: Ruben Smits <ruben.smits@intermodalics.eu>
new rtt version

Signed-off-by: Ruben Smits <ruben.smits@intermodalics.eu>
updated rtt to v2.7.0-rc8

Signed-off-by: Ruben Smits <ruben.smits@intermodalics.eu>
update submodules

Signed-off-by: Johannes Meyer <johannes@intermodalics.eu>
Merge remote-tracking branch 'origin/master' into toolchain-2.7