Makefile: Make it uniform with other projects

Signed-off-by: Vaibhav Gupta <vaibhav.gupta@cern.ch>

Makefile

@@ -9,6 +9,12 @@ DIRS = $(C_DIRS) \
      Documentation/fmc
 
 all clean cleanall install: $(DIRS)
+clean: TARGET = clean
+cleanall: TARGET = cleanall
+install: TARGET = install
+
+$(DIRS):
+	$(MAKE) -C $@ $(TARGET)
 
 modules modules_install:
 	@$(MAKE) -C drivers/fmc/ $@