Cleaned up mount code

Author: pradosh-arduino

source/kernel/C/shell/commands/mount.c

@@ -16,12 +16,16 @@
 
 int cmd_mount(int argc, char** argv)
 {
-    if (argc < 3) {
-        printf("Usage: mount <device> <mount_point>");
+    if(argc == 1){
         list_all_mounts();
         return 0;
     }
 
+    if (argc < 3) {
+        printf("Usage: mount <device> <mount_point>");
+        return -1;
+    }
+
     const char* device = argv[1];
     const char* mount_point = argv[2];