configs: nitrogen*: bump kernel version to 3.14.52-1.1.0_ga

configs: nitrogen*: bump kernel version to 3.14.52-1.1.0_ga

Also add device tree of our Nitrogen6_Max QuadPlus version:
https://boundarydevices.com/product/nitrogen6max/

As well as our latest SOM version:
https://boundarydevices.com/product/nit6x-som-v2/

Using the latest commit of our 3.14.52 kernel branch:
https://github.com/boundarydevices/linux-imx6/commits/boundary-imx_3.14.52_1.1.0_ga

Signed-off-by: Gary Bisson <gary.bisson@boundarydevices.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>