kernel-2.eclass: Fix LICENSE for Linux 4.14 and later.
Starting with version 4.14, the whole firmware tree has been dropped
from the kernel:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=
b38923a068c10fc36ca8f596d650d095ce390b85
Therefore including "linux-firmware" in LICENSE is no longer accurate.
Closes: https://bugs.gentoo.org/677756
Reviewed-by: Mike Pagano <mpagano@gentoo.org>
Reviewed-by: Alice Ferrazzi <alicef@gentoo.org>
Signed-off-by: Ulrich Müller <ulm@gentoo.org>