Kbuild: Enforce build variant user when building in-tree

The kernel doesn't export this: enforce to user to remove
unnecessary debugging.

Change-Id: I9ea9eb7a735e92db6b2e14a10eb201fcd99221d1
diff --git a/Kbuild b/Kbuild
index 0d71ffd..6d71214 100644
--- a/Kbuild
+++ b/Kbuild
@@ -14,6 +14,10 @@
 	WLAN_COMMON_INC := $(WLAN_ROOT)/$(WLAN_COMMON_ROOT)
 	WLAN_FW_API := $(WLAN_ROOT)/../fw-api/
 	WLAN_PROFILE := default
+
+	# Disable debugging by forcing BUILD_VARIANT user if
+	# we are building this outside of Android
+	TARGET_BUILD_VARIANT := user
 endif
 
 WLAN_COMMON_ROOT ?= ../qca-wifi-host-cmn