Merge #230

230: MSP432 platform support r=jrvanwhy a=lebakassemmerl

### Summary

Since around two weeks the tock-kernel supports the MSP432 platform, so this PR adds MSP432-support for the userspace.
I only adopted the flash-script and the makefile and added a linker-script for the board.

Flashing apps is currently only possible with openOCD, the makefile in the kernel provides a target to do this.

Co-authored-by: hotschi <hotschi@gmx.at>
diff --git a/tock b/tock
index 6e38588..6260afa 160000
--- a/tock
+++ b/tock
@@ -1 +1 @@
-Subproject commit 6e38588c73dbd78d274c00ae7fb7789b78cf6856
+Subproject commit 6260afac204ae9f469abe9e2573cb51d3b124624