[Matrix] [HLSL] Define a `fmatrix-default-layout=` in the Clang Driver

[farzonl]

The matrix feature today has an IR pass that can toggle between row major and column major.
This flag is exposed in opt and somlir-opt and opt can both be used to invoke -matrix-default-layout=column-major or -matrix-default-layout=row-major.

What we need is the clang driver to add -mllvm -matrix-default-layout=*-major so the existing matrix pass will shift its major order.

This needs to be a cc1 flag. It will also block us from starting #166410.

[llvmbot]

@llvm/issue-subscribers-clang-driver

Author: Farzon Lotfi (farzonl)

The matrix feature today has an IR pass that can toggle between row major and column major. This flag is exposed in opt and so`mlir-opt` and `opt` can both be used to invoke `-matrix-default-layout=column-major` or ` -matrix-default-layout=row-major`.

What we need is the clang driver to add -mllvm -matrix-default-layout=*-major so the existing matrix pass will shift its major order.

This needs to be a cc1 flag. It will also block us from starting #166410.