[LEDE-DEV] [RFC] brcm47xx: bump kernel to 4.4

[p.wassi at gmx.at]

> It seems I'm experiencing the same crazy problem. Local builds work
> for me (as explained in commit message), but image from buildbot
> doesn't boot. This is some totally crazy thing :|

I opt for staying at 4.4 and not reverting, since the issue already occured
on kernel 4.1 for the WRT54GL (and probably other devices as well?).
So it's _not_ a 4.1 -> 4.4 issue! The last kernel, that booted fine
on my devices (with buildbot images) was OpenWRT 15.05.1 - 3.18.23
As you've experienced yourself: local images also work fine. With 4.1 and 4.4.

Best regards,
P. Wassi