drm/locking: fix __stack_depot_* name conflict

Commit cd06ab2fd48f ("drm/locking: add backtrace for locking contended
locks without backoff") added functions named __stack_depot_* in drm
which conflict with stack depot. Rename to __drm_stack_depot_*.

v2 by Jani:
- Also rename __stack_depot_print

References: https://lore.kernel.org/r/[e-mail]
Fixes: cd06ab2fd48f ("drm/locking: add backtrace for locking contended locks without backoff")
Cc: Daniel Vetter <[e-mail]>
Reviewed-by: Daniel Vetter <[e-mail]>
Signed-off-by: Stephen Rothwell <[e-mail]>
Signed-off-by: Jani Nikula <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]
(cherry picked from commit c4f08d7246a520da5f2b1068f635da0678485e33)

drivers/gpu/drm/drm_modeset_lock.c

···
 static DEFINE_WW_CLASS(crtc_ww_class);
 
 #if IS_ENABLED(CONFIG_DRM_DEBUG_MODESET_LOCK)
-static noinline depot_stack_handle_t __stack_depot_save(void)
+static noinline depot_stack_handle_t __drm_stack_depot_save(void)
 {
 	unsigned long entries[8];
 	unsigned int n;
···
 	return stack_depot_save(entries, n, GFP_NOWAIT | __GFP_NOWARN);
 }
 
-static void __stack_depot_print(depot_stack_handle_t stack_depot)
+static void __drm_stack_depot_print(depot_stack_handle_t stack_depot)
 {
 	struct drm_printer p = drm_debug_printer("drm_modeset_lock");
 	unsigned long *entries;
···
 	kfree(buf);
 }
 #else /* CONFIG_DRM_DEBUG_MODESET_LOCK */
-static depot_stack_handle_t __stack_depot_save(void)
+static depot_stack_handle_t __drm_stack_depot_save(void)
 {
 	return 0;
 }
-static void __stack_depot_print(depot_stack_handle_t stack_depot)
+static void __drm_stack_depot_print(depot_stack_handle_t stack_depot)
 {
 }
 #endif /* CONFIG_DRM_DEBUG_MODESET_LOCK */
···
 void drm_modeset_drop_locks(struct drm_modeset_acquire_ctx *ctx)
 {
 	if (WARN_ON(ctx->contended))
-		__stack_depot_print(ctx->stack_depot);
+		__drm_stack_depot_print(ctx->stack_depot);
 
 	while (!list_empty(&ctx->locked)) {
 		struct drm_modeset_lock *lock;
···
 	int ret;
 
 	if (WARN_ON(ctx->contended))
-		__stack_depot_print(ctx->stack_depot);
+		__drm_stack_depot_print(ctx->stack_depot);
 
 	if (ctx->trylock_only) {
 		lockdep_assert_held(&ctx->ww_ctx);
···
 		ret = 0;
 	} else if (ret == -EDEADLK) {
 		ctx->contended = lock;
-		ctx->stack_depot = __stack_depot_save();
+		ctx->stack_depot = __drm_stack_depot_save();
 	}
 
 	return ret;