Segfault in ldiv

DFTK users report segfault using AMDGPU in their routines.

A MWE reproduces the issue:
```
using AMDGPU
using LinearAlgebra

# Any tall ROCMatrix triggers it
A = ROCArray(randn(Float64, 10, 5))
b = ROCArray(randn(Float64, 10))

F = qr(A)
F \ b
```

A fix is avail in #941 

cc @mfherbst 