panvk: Stop using pan_blitter for framebuffer preloads
What does this MR do and why?
After appling !31382 (merged), pan_blitter is the only piece of code that where allocation failures are not handled properly. Rather than teaching pan_blitter how to deal with allocation failures, we take this as an opportunity to have a panvk-specific FB preload logic where we can do a few optimizations we wouldn't be able to do if the code was in src/panfrost/lib.
This series is based on !31382 (merged), !31439 (merged) and !31440 (merged). It starts at vk/meta: Support VkShaderExt objects to allow tracking internal shaders
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/cc @gfxstrand for the vk-meta bits
/cc @ericsmith @marysaka for the panvk/panfrost bits