pvr: Provide vertex input data to the compiler

Draft for now since this depends on !21579 (merged) and won't compiler without it.

The driver now allocates vertex input registers based on the graphics pipeline's VkPipelineVertexInputStateCreateInfo and passes that info along to the compiler to use. For now we're doing a DMA per each vertex attribute for simplicity and to get things working quicker but it could do with being a bit more smarter.