dkms-mt7601: to use v3.0.0.4 upsteam src.

Fixes build failure on kernel 3.14 caused by kernel data structure change into
an actual C struct.

It also uses the new v3.0.0.4 upstream sources. The source.tar.bz2 has
been rehosted on github.io.
All these which statement really need to just be tossed, they make no sense.  If the package can't find those commands, you probably couldn't install this to begin with, or even use the system.