mailmap: Use Eric Engestrom's personal email address

Signed-off-by: Eric Engestrom <eric.engestrom@imgtec.com>
diff --git a/.mailmap b/.mailmap
index 756b066..ff60ba7 100644
--- a/.mailmap
+++ b/.mailmap
@@ -148,6 +148,8 @@
 
 Eric Anholt <eric@anholt.net> Eric Anholt <anholt@FreeBSD.org>
 
+Eric Engestrom <eric@engestrom.ch> <eric.engestrom@imgtec.com>
+
 Eugeni Dodonov <eugeni.dodonov@intel.com> <eugeni@mandriva.com>
 
 Fabian Bieler <der.fabe@gmx.net> <fabianbieler@fastmail.fm>