depmod: use array for dependency output

depmod: use array for dependency output

The shared/array implementation is already used within depmod, but not
for dependency output. Adding it here reduces the amount of custom code
in depmod, simplifies auditing, reduces binary size, and has the nice
benefit of slightly faster runtime due to memory reusage.

Signed-off-by: Tobias Stoeckmann <tobias@stoeckmann.org>
Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>
Link: https://github.com/kmod-project/kmod/pull/193
Signed-off-by: Lucas De Marchi <lucas.de.marchi@gmail.com>