mailmap: add Sebastian Reichel

Add two entries to map to my primary kernel address.
Signed-off-by: NSebastian Reichel <sre@kernel.org>

.mailmap

@@ -143,6 +143,8 @@ Santosh Shilimkar <ssantosh@kernel.org>
 Santosh Shilimkar <santosh.shilimkar@oracle.org>
 Sascha Hauer <s.hauer@pengutronix.de>
 S.Çağlar Onur <caglar@pardus.org.tr>
+Sebastian Reichel <sre@kernel.org> <sre@debian.org>
+Sebastian Reichel <sre@kernel.org> <sebastian.reichel@collabora.co.uk>
 Shiraz Hashim <shiraz.linux.kernel@gmail.com> <shiraz.hashim@st.com>
 Shuah Khan <shuah@kernel.org> <shuahkhan@gmail.com>
 Shuah Khan <shuah@kernel.org> <shuah.khan@hp.com>