Convert CONFIG_CMD_TSI148 to Kconfig

This converts the following to Kconfig:
   CONFIG_CMD_TSI148

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
diff --git a/cmd/Kconfig b/cmd/Kconfig
index bb1980d..1ab1cf7 100644
--- a/cmd/Kconfig
+++ b/cmd/Kconfig
@@ -857,6 +857,12 @@
 	help
 	  SPI utility command.
 
+config CMD_TSI148
+	bool "tsi148 - Command to access tsi148 device"
+	help
+	  This provides various sub-commands to initialise and configure the
+	  Turndra tsi148 device. See the command help for full details.
+
 config CMD_USB
 	bool "usb"
 	help