Contributors: Add Xiaomi Mi 5 maintainer

Change-Id: I4643c06b28affcdec3c584d34f72e1f2975d01dd
diff --git a/CONTRIBUTORS.mkdn b/CONTRIBUTORS.mkdn
index 32391ea..88ab92e 100644
--- a/CONTRIBUTORS.mkdn
+++ b/CONTRIBUTORS.mkdn
@@ -185,6 +185,7 @@
 * __Sony Z Ultra GPE (togari_gpe):__ FreeXperia Team
 * __Xiaomi Mi2(s) (aries):__ Michael Zimmermann
 * __Xiaomi Mi3/4 (cancro):__ JoeyRizzoli
+* __Xiaomi Mi5 (gemini):__ bgcngm
 * __Xiaomi Redmi Note 3 (kenzo):__ TheStrix
 * __ZTE Nubia Z9 Max (nx510j):__ dianlujitao