kernel: update kernel 4.4 to 4.4.69

Bump the 17.01 tree kernel to 4.4.69. Trunk 4.4 and 17.01 4.4 have diverged, talked this
through with jow, he was okay with a clean diff against 17.01 and not a backported trunk
patch.

The following patches were applied upstream:

* 062-[1-6]-MIPS-* series
* 042-0004-mtd-bcm47xxpart-fix-parsing-first-block

Reintroduced lantiq/patches-4.4/0050-MIPS-Lantiq-Fix-cascaded-IRQ-setup, as
it was incorrectly included upstream thus dropped from LEDE, but subsequently
reverted upstream. Thanks to Kevin Darbyshire-Bryant for pointing me to it.

  Compile-tested on: ar71xx, ramips/mt7621, x86/64.

  Run-tested on: ar71xx, ramips/mt7621, x86/64.

Signed-off-by: Stijn Segers <francesco.borromini@inventati.org>