Fix build type is empty in version string

Signed-off-by: Peiyuan Song <squallatf@gmail.com>
Change-Id: I97c2e6f8c12ecf828605811019d47a24293c1ebb

Makefile

@@ -94,12 +94,6 @@ endif
 
 export Q ECHO
 
-# Default build string (git branch and commit)
-ifeq (${BUILD_STRING},)
-        BUILD_STRING	:=	$(shell git describe --always --dirty --tags 2> /dev/null)
-endif
-VERSION_STRING		:=	v${VERSION_MAJOR}.${VERSION_MINOR}(${BUILD_TYPE}):${BUILD_STRING}
-
 # The cert_create tool cannot generate certificates individually, so we use the
 # target 'certificates' to create them all
 ifneq (${GENERATE_COT},0)
@@ -281,6 +275,12 @@ else
         LOG_LEVEL	:=	20
 endif
 
+# Default build string (git branch and commit)
+ifeq (${BUILD_STRING},)
+        BUILD_STRING  :=  $(shell git describe --always --dirty --tags 2> /dev/null)
+endif
+VERSION_STRING    :=  v${VERSION_MAJOR}.${VERSION_MINOR}(${BUILD_TYPE}):${BUILD_STRING}
+
 ifeq (${AARCH32_INSTRUCTION_SET},A32)
 TF_CFLAGS_aarch32	+=	-marm
 else ifeq (${AARCH32_INSTRUCTION_SET},T32)