.mailmap: update email address for Christopher Obbard

Update my email address.

Link: https://lkml.kernel.org/r/20250122-wip-obbardc-update-email-v2-1-12bde6b79ad0@linaro.org
Signed-off-by: Christopher Obbard <christopher.obbard@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Author: obbardc

.mailmap

@@ -165,6 +165,7 @@ Christian Brauner <brauner@kernel.org> <christian.brauner@canonical.com>
 Christian Brauner <brauner@kernel.org> <christian.brauner@ubuntu.com>
 Christian Marangi <ansuelsmth@gmail.com>
 Christophe Ricard <christophe.ricard@gmail.com>
+Christopher Obbard <christopher.obbard@linaro.org> <chris.obbard@collabora.com>
 Christoph Hellwig <hch@lst.de>
 Chuck Lever <chuck.lever@oracle.com> <cel@kernel.org>
 Chuck Lever <chuck.lever@oracle.com> <cel@netapp.com>