etcd: Allow etcd to run on arm64
etcd: Allow etcd to run on arm64

The etcd maintainers have yet to declare arm64 "officially"
supported. Even though they make binaries available and are aware of
folks using etcd on arm64 targets they still have you "sign the dotted
line" to say you are aware of the lack of support.

See https://github.com/etcd-io/etcd/issues/9077 for some related
discussions.

We update the install to add the ETCD_UNSUPPORTED_ARCH environment
setting to allow etcd to run on arm64.

Signed-off-by: Mark Asselstine <9d979f2c41783077c213bce515ff7ad668691d2c@windriver.com>

OverC/meta-overc,OverC/meta-overc,OverC/meta-overc,masselstine/meta-overc,masselstine/meta-overc,OverC/meta-overc,masselstine/meta-overc,OverC/meta-overc,OverC/meta-overc,masselstine/meta-overc