Fix 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.
Trimming unneeded lines
removing CMD=$(which cmd) style things
Merge pull request #905 from ddaygold/dkms-mt7601

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