drm/xe: Introduce xe_tile_is_root helper

Instead of looking at the tile->id member provide a small helper
to explicitly express our intentions.

Signed-off-by: Michal Wajdeczko <[e-mail]>
Reviewed-by: Piotr Piórkowski <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

drivers/gpu/drm/xe/xe_gsc_proxy.c

···
 #include "xe_map.h"
 #include "xe_mmio.h"
 #include "xe_pm.h"
+#include "xe_tile.h"
 
 /*
  * GSC proxy:
···
 	}
 
 	/* no multi-tile devices with this feature yet */
-	if (tile->id > 0) {
+	if (!xe_tile_is_root(tile)) {
 		xe_gt_err(gt, "unexpected GSC proxy init on tile %u\n", tile->id);
 		return -EINVAL;
 	}

drivers/gpu/drm/xe/xe_irq.c

···
 #include "xe_mmio.h"
 #include "xe_pxp.h"
 #include "xe_sriov.h"
+#include "xe_tile.h"
 
 /*
  * Interrupt registers for a unit are always consecutive and ordered
···
 
 static void dg1_irq_reset(struct xe_tile *tile)
 {
-	if (tile->id == 0)
+	if (xe_tile_is_root(tile))
 		dg1_intr_disable(tile_to_xe(tile));
 
 	gt_irq_reset(tile);

drivers/gpu/drm/xe/xe_tile.h

···
 	return NULL;
 }
 #endif
+
+static inline bool xe_tile_is_root(struct xe_tile *tile)
+{
+	return tile->id == 0;
+}
+
 #endif