Older Book-E processors (e500v1/e500v2) don't support dcbzl.

The only difference between dcbzl and dcbz is dcbzl operates on native cache
line lengths regardless of L1CSR0[DCBZ32]. Since we don't change the cache line
size, the cacheline_size variable will reflect the used cache line length, and
dcbz will work as expected.