pci: Drop dm.h inclusion from header file

The layerscape header should not include dm.h so remove it.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/pci/pcie_layerscape_fixup.c b/drivers/pci/pcie_layerscape_fixup.c
index 94de4ed..8315b0b 100644
--- a/drivers/pci/pcie_layerscape_fixup.c
+++ b/drivers/pci/pcie_layerscape_fixup.c
@@ -6,6 +6,7 @@
  */
 
 #include <common.h>
+#include <dm.h>
 #include <init.h>
 #include <log.h>
 #include <pci.h>