Introduce the bbappend for v5.14 and also set the default kernel to
v5.14 for all the boards.
(From meta-yocto rev: bed70a64b5b772fd71a7ff88a9f3719082e9398c)
Signed-off-by: Kevin Hao <kexin.hao@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
