v3d: free dbuf

Fix a leak found with address sanitizer and
`dEQP-GLES31.functional.shaders.helper_invocation.derivate.wide_lines_max_samples_dfdx`.

Fixes: 9a9f2812519 ("v3d: support blitting straight from tile buffer")
Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>
Signed-off-by: Juan A. Suarez Romero <jasuarez@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/30444>
1 file changed