blas: Improve error on missing rocBLAS

[jpsamaroo]

Now:

julia> qr(A)
ERROR: ArgumentError: rocBLAS is not available
Stacktrace:
 [1] lib_state()
   @ AMDGPU.rocBLAS ~/.julia/dev/AMDGPU/src/blas/rocBLAS.jl:41
 [2] handle()
   @ AMDGPU.rocBLAS ~/.julia/dev/AMDGPU/src/blas/rocBLAS.jl:49
 [3] geqrf!(A::ROCMatrix{ComplexF64, AMDGPU.Runtime.Mem.HIPBuffer})
   @ AMDGPU.rocSOLVER ~/.julia/dev/AMDGPU/src/solver/highlevel.jl:13
 [4] qr!(A::ROCMatrix{ComplexF64, AMDGPU.Runtime.Mem.HIPBuffer})
   @ AMDGPU.rocSOLVER ~/.julia/dev/AMDGPU/src/solver/highlevel.jl:206
 [5] qr(::ROCMatrix{ComplexF64, AMDGPU.Runtime.Mem.HIPBuffer}; kwargs::Base.Pairs{Symbol, Union{}, Tuple{}, NamedTuple{(), Tuple{}}})
   @ LinearAlgebra ~/.julia/juliaup/julia-1.9.2+0.x64.linux.gnu/share/julia/stdlib/v1.9/LinearAlgebra/src/qr.jl:428
 [6] qr(::ROCMatrix{ComplexF64, AMDGPU.Runtime.Mem.HIPBuffer})
   @ LinearAlgebra ~/.julia/juliaup/julia-1.9.2+0.x64.linux.gnu/share/julia/stdlib/v1.9/LinearAlgebra/src/qr.jl:425
 [7] top-level scope
   @ REPL[6]:1

Fixes #461

[pxl-th]

Maybe instead of checking every time we access the library state, we should check only once in rocBLAS.create_handle method?

[jpsamaroo]

Oops, yeah, that would have been better 😅 Thanks for fixing that and others!