Add SparseArrays functionality for CuSparseDeviceColumnView

[Zinoex]

I have a usecase where I effectively need to iterate columns of a sparse matrix and access its nonzero indices and values, which fails without the functions added in this PR. And preferably, I would want to avoid to manually keep track of the internals during the iteration.

Below I attach a MWE to that fails to compile without the added functions. The concrete usecase is more complicated than the MWE with other additional logic and computation, and multiple threads per column, but it is not important to show the error.

using CUDA, SparseArrays

function mwe()
    A = cu(sprand(1000, 1000, 0.01))
    @cuda threads=256 kernel(A)
end

function kernel(A)
    i = threadIdx().x
    while i <= size(A, 2)
        col = @view A[:, i]
        inds = rowvals(col)
        vals = nonzeros(col)
        num_nonzeros = nnz(col)

        v = col[inds[1]]

        i += blockDim().x
    end
end

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diff --git a/lib/cusparse/device.jl b/lib/cusparse/device.jl
index 90a7b5e6f..aa6778d5d 100644
--- a/lib/cusparse/device.jl
+++ b/lib/cusparse/device.jl
@@ -23,7 +23,7 @@ Base.length(g::CuSparseDeviceVector) = g.len
 Base.size(g::CuSparseDeviceVector) = (g.len,)
 SparseArrays.nnz(g::CuSparseDeviceVector) = g.nnz
 
-struct CuSparseDeviceMatrixCSC{Tv,Ti,A} <: SparseArrays.AbstractSparseMatrixCSC{Tv,Ti}
+struct CuSparseDeviceMatrixCSC{Tv, Ti, A} <: SparseArrays.AbstractSparseMatrixCSC{Tv, Ti}
     colPtr::CuDeviceVector{Ti, A}
     rowVal::CuDeviceVector{Ti, A}
     nzVal::CuDeviceVector{Tv, A}