Use TARGET_SCREEN_DENSITY

This variable is used to auto-populate the ro.sf.lcd_density as
well as selecting density bucket for resources in recovery.
diff --git a/enchilada/BoardConfig.mk b/enchilada/BoardConfig.mk
index ecb3676..85e378d 100644
--- a/enchilada/BoardConfig.mk
+++ b/enchilada/BoardConfig.mk
@@ -4,6 +4,7 @@
 # Board Information
 TARGET_BOOTLOADER_BOARD_NAME := enchilada
 TARGET_BOARD_PLATFORM := enchilada
+TARGET_SCREEN_DENSITY := 400
 
 # Kernel/boot.img Configuration
 BOARD_KERNEL_CMDLINE     += androidboot.hardware=enchilada