radeonsi: vpe: fix noisy false error

When running `ffmpeg -vaapi_device /dev/dri/renderD128 -f lavfi -i smptebars=duration=5:size=1280x720:rate=30 -vf format=rgba,hwupload,scale_vaapi=format=nv12,hwdownload  testout.mp4`,

the vpe is asked to transform into NV12, which cannot be done with a blit. `si_vpe_construct_blt` fails, but then it gracefully falls back into `vlVaPostProcCompositor` and finishes the task correctly, but not before logging the error:

SIVPE ERROR ../mesa-25.1.3/src/gallium/drivers/radeonsi/si_vpe.c:1095 si_vpe_construct_blt Failed in checking process operation and build settings(9)

for each frame that is processed. Since this is expected, my original thought was to demote this to a warning. But looking at all the reasons it could fail for, there already is a warning (or error) logged, so it seems to me the best thing to do is remove the error entirely

There may be a better approach here, and I'm all ears.

Fixes: e85a6b6a63 ("radeonsi/vpe: check reduction ratio")
Reviewed-by: Peyton Lee <peytolee@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/35449>

src/gallium/drivers/radeonsi/si_vpe.c

@@ -1186,7 +1186,6 @@ si_vpe_construct_blt(struct vpe_video_processor *vpeproc,
     */
    result = si_vpe_processor_check_and_build_settins(vpeproc, process_properties, src_surfaces, dst_surfaces);
    if (VPE_STATUS_OK != result) {
-      SIVPE_ERR("Failed in checking process operation and build settings(%d)\n", result);
       return result;
    }