.mailmap: add an alias for Samuel Li

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/1999>
diff --git a/.mailmap b/.mailmap
index dce2926..f2a0fdc 100644
--- a/.mailmap
+++ b/.mailmap
@@ -531,6 +531,8 @@
 
 Samuel Iglesias Gonsálvez <siglesias@igalia.com> Samuel Iglesias Gonsalvez <siglesias@igalia.com>
 
+Samuel Li <samuel.li@amd.com> <Samuel.Li@amd.com>
+
 Sean D'Epagnier <sean@depagnier.com> <geckosenator@freedesktop.org>
 
 Serge Martin <edb+mesa@sigluy.net> Serge Martin (EdB) <edb+mesa@sigluy.net>