dm: MIGRATION: Update migration plan for DM_SPI_FLASH

Migration plan for DM_SPI_FLASH is v2019.07 since it
depends on DM_SPI migration.

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
diff --git a/Makefile b/Makefile
index c4d827f..3e926d8 100644
--- a/Makefile
+++ b/Makefile
@@ -965,6 +965,16 @@
 	@echo >&2 "===================================================="
 endif
 endif
+ifeq ($(CONFIG_SPI_FLASH),y)
+ifneq ($(CONFIG_DM_SPI_FLASH)$(CONFIG_OF_CONTROL),yy)
+	@echo >&2 "===================== WARNING ======================"
+	@echo >&2 "This board does not use CONFIG_DM_SPI_FLASH. Please update"
+	@echo >&2 "the board to use CONFIG_SPI_FLASH 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
 	@# Check that this build does not use CONFIG options that we do not
 	@# know about unless they are in Kconfig. All the existing CONFIG
 	@# options are whitelisted, so new ones should not be added.