drm/etnaviv: use dma_resv_describe

Instead of dumping the fence info manually.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Rob Clark <robdclark@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211103081231.18578-4-christian.koenig@amd.com