get_module_deps3.py: Check attribute '__file__'

Check if the module object has attribute '__file__' to fix and
avoid errors like:

AttributeError: module '_abc' has no attribute '__file__'. Did you mean: '__name__'?

Signed-off-by: Leon Anavi <leon.anavi@konsulko.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
(cherry picked from commit 8acce12c)
Signed-off-by: Steve Sakoman <steve@sakoman.com>