driver: Add a zplgtr in order to initiate trapezoidal matrix with the std api
zplgsy/zplghe standard API to not allow for initialization of non triangular matrices.
Instead of changing the interface, we propose to add a new interface that internally calls pzplgsy to generated trapezoidal matrices.
@all Please approve or comment. I'll merge it if I get multiple approval.
Edited by Mathieu Faverge