vo_gpu: use actual (not logical) texture dimension

pass_upload_image currently stores the logical dimensions, which
in case of vulkan decoding may not match the physical one (e.g
1088 for 1080p). this mismatch results in glitches when using
polar scalers.

fix this by using the actual texture dimensions for hwdec plane
sizes.

Fixes: https://github.com/mpv-player/mpv/issues/14944