zenfone6: remove duplicate flags in Boardconfig

Change-Id: I2f569d0f89b68b7bb20e5ee54d9a4a561d0c33ec
diff --git a/BoardConfig.mk b/BoardConfig.mk
index cfa4d74..ce603ec 100755
--- a/BoardConfig.mk
+++ b/BoardConfig.mk
@@ -98,8 +98,6 @@
 TARGET_SUPPORTS_32_BIT_APPS := true
 TARGET_SUPPORTS_64_BIT_APPS := true
 TARGET_USES_QCOM_BSP := false
-TARGET_USERIMAGES_USE_EXT4 := true
-TARGET_USERIMAGES_USE_F2FS := false
 TARGET_USERIMAGES_SPARSE_EXT_DISABLED := false
 
 # Kernel