mailmap: Fix Reimar Döffinger name

This probably happened when interpreting the utf8 name as latin1.

Fixes dbbaaff6 and f4e94dfe.
Signed-off-by: NPhilippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: NThomas Huth <thuth@redhat.com>

.mailmap

@@ -33,5 +33,6 @@ Justin Terry (VM) <juterry@microsoft.com> Justin Terry (VM) via Qemu-devel <qemu
 
 
 # Also list preferred name forms where people have changed their
-# git author config
+# git author config, or having utf8/latin1 encoding issues.
 Daniel P. Berrangé <berrange@redhat.com>
+Reimar Döffinger <Reimar.Doeffinger@gmx.de>