drm/i915/gvt: Constify gtt_type_table_entry

It is never modified, so make it const to allow the compiler to put it
in read-only memory.

Signed-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com>
Signed-off-by: Zhi Wang <zhi.a.wang@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20211204105527.15741-9-rikard.falkeborn@gmail.com


Reviewed-by: Zhi Wang <zhi.a.wang@intel.com>