MAGMA isn't compatible with CUDA 11 (#17753)

Co-authored-by: Axel Huebl <axel.huebl@plasma.ninja>
Co-authored-by: Adam J. Stewart <ajstewart426@gmail.com>

var/spack/repos/builtin/packages/magma/package.py

@@ -36,6 +36,7 @@ class Magma(CMakePackage, CudaPackage):
     depends_on('blas')
     depends_on('lapack')
     depends_on('cuda@8:', when='@2.5.1:')  # See PR #14471
+    depends_on('cuda@:10', when='@:2.5.3')  # incompatible with CUDA 11
 
     conflicts('~cuda', msg='Magma requires cuda')
     conflicts('cuda_arch=none',