Remove MK_INFO guards in bsd.info.mk per r276556

Remove MK_INFO guards in bsd.info.mk per r276556

As a side-effect now info pages will always be built/installed if
MK_INFO == yes, whereas before their presence was conditional based on the
value of MK_INFO

This .mk file might be removed in the future, pending discussion on -arch. For
now unbreak its use outside of src (with the only use in ports according to
bapt being devel/cvs*)

X-MFC with: r276551, r276556
Reviewed by: bapt
Differential Revision: D1413