Fix bug in dependency checking

By adding VERSION_FILE to the PHONY targets the script
/tools/setlocalversion is always called and version_autogenerated.h
is replaced only if the script find a modified source file.

Signed-off-by: Stefano Babic <sbabic@denx.de>

Makefile

@@ -244,7 +244,7 @@ LIBS += libfdt/libfdt.a
 LIBS += api/libapi.a
 
 LIBS := $(addprefix $(obj),$(LIBS))
-.PHONY : $(LIBS)
+.PHONY : $(LIBS) $(VERSION_FILE)
 
 # Add GCC lib
 PLATFORM_LIBS += -L $(shell dirname `$(CC) $(CFLAGS) -print-libgcc-file-name`) -lgcc