Revert "Add FINSH_CMD_SIZE option."

This reverts commit 326a7d7496eba1231a28c1681671ef0e54b4902f.

components/finsh/shell.h

@@ -50,9 +50,7 @@
 #ifndef FINSH_THREAD_STACK_SIZE
 #define FINSH_THREAD_STACK_SIZE 2048
 #endif
-#ifndef FINSH_CMD_SIZE
 #define FINSH_CMD_SIZE		80
-#endif
 
 #define FINSH_OPTION_ECHO	0x01
 #if defined(FINSH_USING_MSH) || (defined(RT_USING_DFS) && defined(DFS_USING_WORKDIR))