Ensure the kernel component don't call userspace API

Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>

fs/mmap/fs_mmap.c

@@ -193,9 +193,7 @@ FAR void *mmap(FAR void *start, size_t length, int prot, int flags,
 
       return rammap(fd, length, offset);
 #else
-      /* Error out.  The errno value was already set by ioctl() */
-
-      ferr("ERROR: ioctl(FIOC_MMAP) failed: %d\n", ret);
+      ferr("ERROR: nx_ioctl(FIOC_MMAP) failed: %d\n", ret);
       goto errout;
 #endif
     }

fs/mmap/fs_rammap.c

@@ -170,7 +170,7 @@ FAR void *rammap(int fd, size_t length, off_t offset)
             {
               /* All other read errors are bad. */
 
-              ferr("ERROR: Read failed: offset=%d errno=%d\n",
+              ferr("ERROR: Read failed: offset=%d ret=%d\n",
                    (int)offset, (int)nread);
 
               ret = nread;