When parity is higher than 5, the rs_vand decoding matrix is not invertible
for some combinations of missing data and parity.
Add new backend with modified gen matrix that is suited when parity >=
5.
Use rs_cauchy or new modified matrix when parity >= 5.
Related-Bug: #1639691
Co-Authored-By: Tim Burke <tim.burke@gmail.com>
Change-Id: I09abfc619893da7fd3d0740fed3586fdd46791d9
5d25e4a663