Log Message:
x11/gtkmm3: remove redundant dependencies

pkglint says:

NOTE: Makefile:30: The requirement >=2.24.2 is already guaranteed by the \ 
>=2.24.3nb2 from ../../devel/atkmm/buildlink3.mk:11.
NOTE: Makefile:33: The requirement >=2.49.1 is already guaranteed by the \ 
>=2.62.0nb1 from ../../devel/glibmm/buildlink3.mk:9.
NOTE: Makefile:36: The requirement >=2.38.2 is already guaranteed by the \ 
>=2.42.0nb3 from ../../devel/pangomm/buildlink3.mk:9.
NOTE: Makefile:38: The requirement >=1.12.0 is already guaranteed by the \ 
>=1.12.2nb3 from ../../graphics/cairomm/buildlink3.mk:9.
NOTE: Makefile:40: The requirement >=2.35.5 is already guaranteed by the \ 
>=2.40.0nb1 from ../../graphics/gdk-pixbuf2/buildlink3.mk:9.
NOTE: Makefile:43: The requirement >=3.22.0 is already guaranteed by the \ 
>=3.24.14nb2 from ../../x11/gtk3/buildlink3.mk:9.