anv: add support for VK_EXT_nested_command_buffer
What does this MR do and why?
anv: add support for VK_EXT_nested_command_buffer
Our implementation of secondary command buffers already jumps into them and edits the end of the secondary command buffer to jump back into the primary.
That implementation can work just the same with any levels of secondary. The only possible issue would happen with a secondary calling itself, but that's not possible.
Signed-off-by: Lionel Landwerlin lionel.g.landwerlin@intel.com