sys/vfs/hammer2: Use correct XOP struct in hammer2_xop_{lookup,delete}

sys/vfs/hammer2: Use correct XOP struct in hammer2_xop_{lookup,delete}

Callers of these XOP use hammer2_xop_lookup_t,
but the XOP implementation takes it as hammer2_xop_scanlhc_t.
It was working as the definition of these structs are the same.

Apparently hammer2_xop_lookup() should be using hammer2_xop_lookup_t.
hammer2_xop_delete() should be using hammer2_xop_lookup_t too given
similarity in its implementation (i.e. caller side is correct).