sparse-llvm: Update function calls to use LLVM API changes

[lnocturno]

This patch updates sparse-llvm to use the newer LLVM API functions, replacing the deprecated functions with their updated counterparts:

• Replace LLVMConstGEP with LLVMConstGEP2
• Replace LLVMBuildInBoundsGEP with LLVMBuildInBoundsGEP2
• Replace LLVMBuildLoad with LLVMBuildLoad2
• Replace LLVMBuildCall with LLVMBuildCall2

The patch also ensures that the correct element types are passed to the new functions as required.