anv: multiply the scratch space by 4 on gen9-10 like iris and i965

anv: multiply the scratch space by 4 on gen9-10 like iris and i965

My understanding is that there's no reason for the scratch space
allocation to be different between iris, i965 and anv. Let's make all
the functions behave the same.

I don't know if this fixes any specific gen9 bugs, it it might since
it increases the scratch space.

v2: Rebase.
v3: Rebase.
v4: Remove redundant gen 11 check (Jason).

Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Tested-by: Marge Bot <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4006>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4006>