target: Add API for identifying build type

Add API for finding user variant build

Change-Id: Ia91f21ba8a934707bcd640ef234238a6994cb6a0
diff --git a/include/target.h b/include/target.h
index 4a2891c..772afdf 100644
--- a/include/target.h
+++ b/include/target.h
@@ -85,4 +85,5 @@
 void ulpi_write(unsigned val, unsigned reg);
 void target_crypto_init_params(void);
 int target_cont_splash_screen(void);
+bool target_build_variant_user();
 #endif