intel_th: msu: Use the real device in case of IOMMU domain allocation

When allocating DMA buffers for the MSU, use the real device instead
of GTH.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>

drivers/hwtracing/intel_th/msu.c

@@ -709,17 +709,17 @@ static int msc_buffer_win_alloc(struct msc *msc, unsigned int nr_blocks)
 	}
 
 	for (i = 0; i < nr_blocks; i++) {
-		win->block[i].bdesc = dma_alloc_coherent(msc_dev(msc), size,
-							 &win->block[i].addr,
-							 GFP_KERNEL);
+		win->block[i].bdesc =
+			dma_alloc_coherent(msc_dev(msc)->parent->parent, size,
+					   &win->block[i].addr, GFP_KERNEL);
+
+		if (!win->block[i].bdesc)
+			goto err_nomem;
 
 #ifdef CONFIG_X86
 		/* Set the page as uncached */
 		set_memory_uc((unsigned long)win->block[i].bdesc, 1);
 #endif
-
-		if (!win->block[i].bdesc)
-			goto err_nomem;
 	}
 
 	win->msc = msc;