support devices without bootpartition

if device has no /boot partition, then add the following flag in BoardConfig.mk

TW_HAS_NO_BOOT_PARTITION

Signed-off-by: ChampionSwimmer <android@championswimmer.tk>

Change-Id: I92b36b2e6ca690e2422b36004ae9bb315d24a7c2
diff --git a/Android.mk b/Android.mk
index 1ad1e0d..58b0607 100644
--- a/Android.mk
+++ b/Android.mk
@@ -141,6 +141,9 @@
 ifeq ($(TW_HAS_NO_RECOVERY_PARTITION), true)
     LOCAL_CFLAGS += -DTW_HAS_NO_RECOVERY_PARTITION
 endif
+ifeq ($(TW_HAS_NO_BOOT_PARTITION), true)
+    LOCAL_CFLAGS += -DTW_HAS_NO_BOOT_PARTITION
+endif
 ifeq ($(TW_NO_REBOOT_BOOTLOADER), true)
     LOCAL_CFLAGS += -DTW_NO_REBOOT_BOOTLOADER
 endif