modula2: tidyup M2Dependent.mod

This patch tidies up M2Dependent.mod by introducing a new procedure
to initialize all fields of DependencyList.

gcc/m2/ChangeLog:

	* gm2-libs/M2Dependent.mod (InitDependencyList): New
	procedure.
	(CreateModule): Call InitDependencyList to initialize
	all fields of DependencyList.

Signed-off-by: Gaius Mulley <gaiusmod2@gmail.com>