drm/i915/gvt: Constify cmd_interrupt_events

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/20211204105527.15741-7-rikard.falkeborn@gmail.comReviewed-by: Zhi Wang <zhi.a.wang@intel.com>

drivers/gpu/drm/i915/gvt/cmd_parser.c

@@ -1144,7 +1144,7 @@ struct cmd_interrupt_event {
 	int mi_user_interrupt;
 };
 
-static struct cmd_interrupt_event cmd_interrupt_events[] = {
+static const struct cmd_interrupt_event cmd_interrupt_events[] = {
 	[RCS0] = {
 		.pipe_control_notify = RCS_PIPE_CONTROL,
 		.mi_flush_dw = INTEL_GVT_EVENT_RESERVED,