sapphire: Define screen density

Change-Id: I897932511609069fcdf996c383a5329b8f731ec9
Signed-off-by: ReStranger <restranger@disroot.org>
diff --git a/BoardConfig.mk b/BoardConfig.mk
index 41809ef..17f76ac 100644
--- a/BoardConfig.mk
+++ b/BoardConfig.mk
@@ -10,4 +10,7 @@
 include device/xiaomi/sm6225-common/BoardConfigCommon.mk
 
 # Inherit the proprietary files
-include vendor/xiaomi/sapphire/BoardConfigVendor.mk
\ No newline at end of file
+include vendor/xiaomi/sapphire/BoardConfigVendor.mk
+
+# Screen density
+TARGET_SCREEN_DENSITY := 440