fix Adapt handling of eltype

workaround for JuliaGPU/GPUArrays.jl#348 but really I was just using Adapt incorrectly here

Author: marius311

src/flat_fields.jl

@@ -549,8 +549,8 @@ function get_Cℓ(f₁::FlatS0, f₂::FlatS0=f₁; Δℓ=50, ℓedges=0:Δℓ:16
     ℓmask = (ℓmag .> minimum(ℓedges)) .&  (ℓmag .< maximum(ℓedges))
     L = ℓmag[ℓmask]
     CLobs = 1/α .* real.(dot.(
-        adapt(Array{Float64},f₁)[:Il, full_plane=true][ℓmask], 
-        adapt(Array{Float64},f₂)[:Il, full_plane=true][ℓmask]
+        adapt(Array,f₁)[:Il, full_plane=true][ℓmask], 
+        adapt(Array,f₂)[:Il, full_plane=true][ℓmask]
     ))
     w = @. nan2zero((2*Cℓfid(L)^2/(2L+1))^-1)
 

src/gpu.jl

@@ -101,8 +101,8 @@ Random.randn(rng::CUDA.CURAND.RNG, T::Random.BitFloatType) =
 
 # perhaps minor type-piracy, but this lets us simulate into a CuArray using the
 # CPU random number generator
-Random.randn!(rng::MersenneTwister, A::CuArray{T}) where {T} = 
-    (A .= adapt(CuArray{T}, randn!(rng, adapt(Array{T},A))))
+Random.randn!(rng::MersenneTwister, A::CuArray) = 
+    (A .= adapt(CuArray, randn!(rng, adapt(Array, A))))
 
 # CUDA makes some copies here as a workaround for JuliaGPU/CuArrays.jl#345 &
 # NVIDIA/cuFFT#2714055 but it doesn't appear to be needed in the R2C case, and