timer: Add a migration message

Some boards still use the old timer mechanism. Set a deadline for them to
update to driver model. Point to some examples as well.

This needs a bit of a strange rule to avoid an error on some boards.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/Makefile b/Makefile
index 58a0c34..0034a84 100644
--- a/Makefile
+++ b/Makefile
@@ -1129,6 +1129,10 @@
 	$(call deprecated,CONFIG_DM_ETH,Ethernet drivers,v2020.07,$(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))
+	@# CONFIG_SYS_TIMER_RATE has brackets in it for some boards which
+	@# confuses this rule. Use if() to send just a single character which
+	@# is enable to tell 'deprecated' that one of these symbols exists
+	$(call deprecated,CONFIG_TIMER,Timer drivers,v2023.01,$(if $(strip $(CONFIG_SYS_TIMER_RATE)$(CONFIG_SYS_TIMER_COUNTER)),x))
 	@# 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.