util: Update makefiles for junit testing

- Have clean remove junit.xml files.
- Remove junit.xml target from cbmem makefile - this is in the top
level Makefile.inc now.
- add distclean targets to makefiles.
- Make sure all makefiles have .PHONY set up.
- rm commands need -f or they will fail if the file they're trying
to remove doesn't exist, causing the build to fail.

Change-Id: I2f0635f2c0a9417e3377a90c8d67103323c4a72f
Signed-off-by: Martin Roth <martinroth@google.com>
Reviewed-on: http://review.coreboot.org/12120
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

util/ectool/Makefile

@@ -38,7 +38,11 @@ install: $(PROGRAM)
 	$(INSTALL) $(PROGRAM) $(PREFIX)/sbin
 
 clean:
-	rm *.o $(PROGRAM)
+	rm -f *.o $(PROGRAM) junit.xml
+
+distclean: clean
 
 %.o: %.c
 	$(CC) $(CFLAGS) -c $^ -I. -o $@
+
+.PHONY: all install clean distclean