drm/i915: make array states static const

Don't populate the read-only array states on the stack but instead it
static. Also makes the object code smaller.
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210915112702.12783-1-colin.king@canonical.com

drivers/gpu/drm/i915/display/intel_display_power.c

@@ -900,7 +900,7 @@ static u32
 sanitize_target_dc_state(struct drm_i915_private *dev_priv,
 			 u32 target_dc_state)
 {
-	u32 states[] = {
+	static const u32 states[] = {
 		DC_STATE_EN_UPTO_DC6,
 		DC_STATE_EN_UPTO_DC5,
 		DC_STATE_EN_DC3CO,