Don't add dependencies on Makefiles when using ninja

Ninja has an implicit dependency on the command being run, and kati will
regenerate the ninja manifest if any read makefile changes, so there is no
need to have dependencies on makefiles.
This won't catch all the cases where LOCAL_ADDITIONAL_DEPENDENCIES contains
a .mk file, because a few users of LOCAL_ADDITIONAL_DEPENDENCIES don't
include base_rules.mk, but it will fix the most common ones.

Bug: 23566977
Change-Id: I66de882421376303ab7233c8ce7274548f6b2199