Convert CONFIG_CMD_IOTRACE to Kconfig

This converts the following to Kconfig:
   CONFIG_CMD_IOTRACE

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/Kconfig b/arch/Kconfig
index a8a13b7..c1b47b4 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -70,6 +70,7 @@
 	select DM_MMC
 	imply CMD_HASH
 	imply CMD_IO
+	imply CMD_IOTRACE
 
 config SH
 	bool "SuperH architecture"