Backport device support for Cudy WR 1300 to 19.07

[Sascha Effert]

Hi,


on https://forum.openwrt.org/t/cudy-wr1300-support/67593/150 some
persons implemented support for The Cudy WR 1300 devices into openwrt
19.07. I would like to get this into the official releases and created
a pull request: https://github.com/openwrt/openwrt/pull/3725

I know, adding new devices in stabi branch is not done by default, but
as stated as in
https://openwrt.org/docs/guide-developer/device-support-policies it is
possibe if the patch is not big and well seperated. I hope, this is the
case in the added commits.

I signed off the commits, but I did this the first time and after
releasing the commits first. I hope I did everything right here.

I am working on a support for the master branch, but I can not test it
before end of the week. I will submit it after I saw it works...

If there are any questions, comments, hints...  I would be glad to read
what I did wrong. I checked
https://openwrt.org/docs/guide-developer/device-support-policies and
https://openwrt.org/submitting-patches and I did my best to follow the
rules described there. But as this is my first pull request for this
project, the probability is good that I missed something...

best

Sascha Effert