v3d: Use util_upload_index_buffer like other drivers.

Saves some upload boilerplate.
10 jobs for !922 with index-upload in 11 minutes and 23 seconds (queued for 1 second)
latest detached
Status Name Job ID Coverage
  Containers Build
passed debian #309299

00:00:21

 
  Build+Test
passed meson-clang #309301

00:10:18

passed meson-clover #309305

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passed meson-main #309304

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passed meson-swr-glvnd #309300

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passed meson-vulkan #309306

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passed scons-llvm #309308

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passed scons-nollvm #309307

00:06:13

passed scons-swr #309302

00:09:14

passed scons-win64 #309303

00:09:49