configs: nitrogen*: bump kernel and u-boot revisions

configs: nitrogen*: bump kernel and u-boot revisions

Here are the main U-Boot modifications:
- Fix second Ethernet port for SoloX
- Fix LCD disable sequence
- Fix LVDS2 as primary display

Here are the main Linux modifications:
- Rebase on top of NXP 4.1.15_2.0.0 branch
- Fix touch screens interrupt conflicts
- Backport tw686x features from mainline
- Fix multiple ft5x06 touch instantiation
- Fix dirty cow vulnerability
- Various improvements to TC358743 driver

Signed-off-by: Gary Bisson <gary.bisson@boundarydevices.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>