mdm9625: disable logs in user builds

Disable LK logging in user variant builds.

Change-Id: Ic82316972c9265e90b06f9f2e9688a4cee324ee4
diff --git a/project/mdm9625.mk b/project/mdm9625.mk
index b9b72aa..f0c4821 100644
--- a/project/mdm9625.mk
+++ b/project/mdm9625.mk
@@ -6,7 +6,11 @@
 
 MODULES += app/aboot
 
+ifeq ($(TARGET_BUILD_VARIANT),user)
+DEBUG := 0
+else
 DEBUG := 1
+endif
 
 #DEFINES += WITH_DEBUG_DCC=1
 DEFINES += WITH_DEBUG_UART=1