[GSoC][PATCH 2/5 v4] submodule--helper: introduce for_each_submodule_list()

Introduce function for_each_submodule_list() and replace a loop in module_init() with a call to it. The new function will also be used in other parts of the system in later patches. Mentored-by: Christian Couder Mentored-by: Stefan Beller

[GSoC][PATCH 2/5 v4] submodule--helper: introduce for_each_submodule_list()

Introduce function for_each_submodule_list() and replace a loop in module_init() with a call to it. The new function will also be used in other parts of the system in later patches. Mentored-by: Christian Couder Mentored-by: Stefan Beller