[Hexagon] Fix deprecated call for data layout size in bits

[janetsc]

Ported from Unity PR - #14378

Updating the codegen for Hexagon call from llvm::DataLayout::getTypeSizeInBits.getFixedSize() to llvm::DataLayout::getTypeSizeInBits.getFixedValue(). This fails in the unity branch because the deprecated warning is an error.

cc: @masahi

[tvm-bot]

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• cc @ibsidorenko _{See #10317 for details}

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