add makefiles to adapt nnom and cmsis-nn for xizi

APP_Framework/Applications/knowing_app/mnist/Makefile

@@ -1,7 +1,9 @@
+SRC_FILES := 
+ifeq ($(CONFIG_APP_MNIST),y)
 SRC_FILES := \
 		main.cpp \
 		mnistmain.c
 	CPPPATHS += -I.
-
+endif
 
 include $(KERNEL_ROOT)/compiler.mk

APP_Framework/Applications/knowing_app/mnist/mnistmain.c

@@ -26,5 +26,3 @@ void mnist_app(void);
 int tfmnist(void) {
     mnist_app();
 }
-
-PRIV_SHELL_CMD_FUNCTION(tfmnist, a mnist test sample, PRIV_SHELL_CMD_MAIN_ATTR);