MFC: 1.155 (without vfs_mount_error()): - Fix MNT_UPDATE for msdosfs, do not allow "export" requests if   MSDOSFS_LARGEFS flag is set.
MFC: 1.155 (without vfs_mount_error()):
- Fix MNT_UPDATE for msdosfs, do not allow "export" requests if
  MSDOSFS_LARGEFS flag is set.

PR:	kern/105412

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase