Android.mk: add missing source file

Add xtest_uuid_helpers.c to 'srcs'.

Signed-off-by: Victor Chong <victor.chong@linaro.org>
Acked-by: Etienne Carriere <etienne.carriere@linaro.org>

Android.mk

@@ -51,7 +51,8 @@ srcs +=	adbg/src/adbg_case.c \
 	stats.c \
 	xtest_helpers.c \
 	xtest_main.c \
-	xtest_test.c
+	xtest_test.c \
+	xtest_uuid_helpers.c
 
 ifeq ($(CFG_SECSTOR_TA_MGMT_PTA),y)
 srcs += install_ta.c