drm/i915/gt: add gt_is_root() helper

The "gt_is_root(struct intel_gt *gt)" helper return true if the
gt is the root gt, which means that its id is 0. Return false
otherwise.

Suggested-by: Michal Wajdeczko <[e-mail]>
Signed-off-by: Andi Shyti <[e-mail]>
Reviewed-by: Michal Wajdeczko <[e-mail]>
Reviewed-by: Andrzej Hajda <[e-mail]>
Signed-off-by: Matthew Auld <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/i915/gt/intel_gt.h

···
 		  ##__VA_ARGS__);					\
 } while (0)
 
+static inline bool gt_is_root(struct intel_gt *gt)
+{
+	return !gt->info.id;
+}
+
 static inline struct intel_gt *uc_to_gt(struct intel_uc *uc)
 {
 	return container_of(uc, struct intel_gt, uc);