mailmap: reflect my gmail as default

Use my gmail instead so that I can easily handle those emails
that CC me.

Signed-off-by: Jason Xing <kernelxing@tencent.com>
Link: https://patch.msgid.link/20260303033720.84108-1-kerneljasonxing@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: JasonXing

.mailmap

@@ -348,6 +348,7 @@ Jarkko Sakkinen <jarkko@kernel.org> <jarkko.sakkinen@opinsys.com>
 Jason Gunthorpe <jgg@ziepe.ca> <jgg@mellanox.com>
 Jason Gunthorpe <jgg@ziepe.ca> <jgg@nvidia.com>
 Jason Gunthorpe <jgg@ziepe.ca> <jgunthorpe@obsidianresearch.com>
+Jason Xing <kerneljasonxing@gmail.com>  <kernelxing@tencent.com>
 <javier@osg.samsung.com> <javier.martinez@collabora.co.uk>
 Javi Merino <javi.merino@kernel.org> <javi.merino@arm.com>
 Jayachandran C <c.jayachandran@gmail.com> <jayachandranc@netlogicmicro.com>