QUDA's device-side RNG needs to be updated to support global volumes > 2^31 - 1

[weinbe2]

As part of initializing QUDA's hypercubic RNG, it needs to compute the global lattice index corresponding to each local site. This is currently accumulated into an int32: https://github.com/lattice/quda/blob/develop/include/kernels/random_init.cuh#L49

For sufficiently large global volumes (such as MILC's 192^3x384 configurations) this can overflow leading to identical streams across different global lattice sites. The high-level solution is to promote this value to a uint64, but that will require further changes under the hood.