meta-g220a: Support gatesgarth

The upstream is updated to support Yocto gatesgarth tag, fix the
meta-g220a layer:
* Remove meta-x86 which is empty and does not support gatesgarth yet;
* Add gatesgarth in meta-g220a layer.

Tested: Verify meta-g220a builds fine with upstream code.

Signed-off-by: Lei YU <yulei.sh@bytedance.com>
Change-Id: I3df212ae4ef46f56eb063087b093e1b500bf28c6
2 files changed