contributors: Add Axon7 maintainers

Change-Id: I60e1fcebd4583ec88ee2369f53fbf29a021e6962
diff --git a/CONTRIBUTORS.mkdn b/CONTRIBUTORS.mkdn
index ab70158..3954506 100644
--- a/CONTRIBUTORS.mkdn
+++ b/CONTRIBUTORS.mkdn
@@ -194,6 +194,7 @@
 * __Xiaomi Redmi 1S (armani):__ fefifofum
 * __Xiaomi Redmi 3/Prime (ido):__ Anik1199
 * __Xiaomi Redmi Note 3 (kenzo):__ TheStrix
+* __ZTE Axon 7 (axon7):__ bmc08gt, c457, tdm
 * __ZTE Nubia Z9 Max (nx510j):__ dianlujitao
 
 FreeXperia Team: