hasvk: Disable non-zero fast clears for 8xMSAA images

hasvk: Disable non-zero fast clears for 8xMSAA images

Using texelFetch to read samples from an 8xMSAA fast cleared image on
Haswell can read transparent black pixels around triangles from where
there should be none. This issue isn't present when using sample
shading, resolving the image using vkCmdResolveImage or in a copy the
image. The easiest way to fix this is by just disabling non-zero fast
clears for 8xMSAA images.

Closes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/7587

Cc: mesa-stable
Reviewed-by: Filip Gawin <filip@gawin.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/21444>