This adds initial support for kernel 4.19 to the x86 target.
The patches and the kernel configurations were copied from kernel 4.14
and then refreshed.
The legacy and the genode target will not support PAE any more because
they use a CPU type which does not support PAE, the generic sub target
still supports PAE.
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>