zephyr: add module name

The module name is now explicitly set in module.yml, this ensures that
building with e.g. cmake does not fail when the directory name is
different (default name if unset is directory name).

Author: Jappie3

zephyr/module.yml

@@ -1,3 +1,4 @@
+name: mbedtls
 build:
   cmake-ext: True
   kconfig-ext: True