mailmap: update Gao Xiang's email addresses

mailmap: update Gao Xiang's email addresses

I've been in Alibaba Cloud for more than one year, mainly to address
cloud-native challenges (such as high-performance container images) for
open source communities.

Update my email addresses on behalf of my current employer (Alibaba Cloud)
to support all my (team) work in this area.  Also add an outdated
@redhat.com address of me.

Link: https://lkml.kernel.org/r/20220719154246.62970-1-xiang@kernel.org
Signed-off-by: Gao Xiang <xiang@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>