gui: allow disabling Flash Current TWRP option

On devices where boot scripts are run and ramdisk contents
are dynamically changed, hash check will always fail
when trying to use Flash Current TWRP option.

Disabling the hash check is not advisable as that would
hardcode the changes made during boot and would nullify
the dynamic nature of such changes.

Instead, provide a BoardConfig flag to hide this option,
along with the related feature to automatically flash TWRP
after a zip.

Usage:
TW_NO_FLASH_CURRENT_TWRP := true

Change-Id: Id307bf60b79ff1bff4ba7dd7f427132f40637289
diff --git a/data.cpp b/data.cpp
index 96e4b5e..6959c82 100755
--- a/data.cpp
+++ b/data.cpp
@@ -771,6 +771,11 @@
 	mPersist.SetValue(TW_TIME_ZONE_GUIOFFSET, "0");
 	mPersist.SetValue(TW_TIME_ZONE_GUIDST, "1");
 	mPersist.SetValue(TW_AUTO_REFLASHTWRP_VAR, "0");
+#ifdef TW_NO_FLASH_CURRENT_TWRP
+	mConst.SetValue("tw_no_flash_current_twrp", "1");
+#else
+	mConst.SetValue("tw_no_flash_current_twrp", "0");
+#endif
 
 	mData.SetValue(TW_ACTION_BUSY, "0");
 	mData.SetValue("tw_wipe_cache", "0");