keyboard: Add a migration message

A few boards still use the old keyboard mechanism. Set a deadline for them
to update to driver model.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/Makefile b/Makefile
index 1885f36..ab32efb 100644
--- a/Makefile
+++ b/Makefile
@@ -1123,6 +1123,7 @@
 		$(CONFIG_WATCHDOG)$(CONFIG_HW_WATCHDOG))
 	$(call deprecated,CONFIG_DM_ETH,Ethernet drivers,v2020.07,$(CONFIG_NET))
 	$(call deprecated,CONFIG_DM_I2C,I2C drivers,v2022.04,$(CONFIG_SYS_I2C_LEGACY))
+	$(call deprecated,CONFIG_DM_KEYBOARD,Keyboard drivers,v2022.10,$(CONFIG_KEYBOARD))
 	@# 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.