drm/i915: switch num_scalers/num_sprites to consider DISPLAY_VER

The numbers of scalers and sprites depend on the display version, so use
it instead of GRAPHICS_VER. We were mixing both, which let me confused
while removing CNL and GRAPHICS_VER == 10.

v2 (Rodrigo): Switch IS_GEMINILAKE to DISPLAY_VER == 10
v3 (Lucas): Change check to DISPLAY_VER >= 9, to cover the GLK's num_scalers,
otherwise it remains set to 0.

Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210728215946.1573015-23-lucas.demarchi@intel.com