Correct compilation errors reported by GCC 10/11
New zfs_type_t value ZFS_TYPE_INVALID is introduced.
Variable initialization is now possible to make GCC happy.
Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: szubersk <szuberskidamian@gmail.com>
Closes #12167
Closes #13103