[GENX] Directly build libGenISAIntrinsics library from IGC submodule

**Is your feature request related to a problem? Please describe**
GENX currently uses a prebuilt libGenISA library binary hard to automate build.

**Describe the solution you would like**
We can add an IGC submodule to build the library directly in the GENX Make script.

We can start with https://github.com/pengtu/intel-graphics-compiler, which contains updates to LLVM 18 opaque pointers. Later on, we shall use https://github.com/intel/intel-graphics-compiler directly.