v3dv: improve asserts for VkPipelineColorBlendStateCreateInfo handling

According to the Vulkan 1.0 spec:

  "attachmentCount is the number of VkPipelineColorBlendAttachmentState
   elements in pAttachments. This value must equal the colorAttachmentCount
   for the subpass in which this pipeline is used."

so let's assert exactly that.

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6766>
1 file changed