This target has been on kernel 4.19 for nine months now [1], and
has had testing support for even longer [2].
This should be long enough to drop support for kernel 4.14.
[1] 545bfbc3a922 ("cns3xxx: switch to kernel 4.19")
[2] c6bebe1a9496 ("cns3xxx: add support for kernel 4.19")
Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>