change mkromfs.c to make standard romfs for file

work in progress on mkromfs.c
enable it to write the correct file header (not for directories yet)

for the format ,check :
https://www.kernel.org/doc/Documentation/filesystems/romfs.txt
mkromfs.c standard romfs for directories

romfs : https://www.kernel.org/doc/Documentation/filesystems/romfs.txt