dm: pci: MIGRATION: Add migration plan for PCI

Add a migration plan for PCI which is an important subsystem in U-Boot.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/Makefile b/Makefile
index dff72a5..22d0731 100644
--- a/Makefile
+++ b/Makefile
@@ -948,6 +948,16 @@
 	@echo >&2 "===================================================="
 endif
 endif
+ifeq ($(CONFIG_PCI),y)
+ifneq ($(CONFIG_DM_PCI),y)
+	@echo >&2 "===================== WARNING ======================"
+	@echo >&2 "This board does not use CONFIG_DM_PCI Please update"
+	@echo >&2 "the board to use CONFIG_DM_PCI before the v2019.07 release."
+	@echo >&2 "Failure to update by the deadline may result in board removal."
+	@echo >&2 "See doc/driver-model/MIGRATION.txt for more info."
+	@echo >&2 "===================================================="
+endif
+endif
 ifeq ($(CONFIG_OF_EMBED),y)
 	@echo >&2 "===================== WARNING ======================"
 	@echo >&2 "CONFIG_OF_EMBED is enabled. This option should only"