Convert CONFIG_LSCHLV2 to Kconfig et al

This converts the following to Kconfig:
   CONFIG_LSCHLV2
   CONFIG_LSXHL

Cc: Michael Walle <michael@walle.cc>
Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Michael Walle <michael@walle.cc>
diff --git a/board/buffalo/lsxl/Kconfig b/board/buffalo/lsxl/Kconfig
index ef78896..fd8f054 100644
--- a/board/buffalo/lsxl/Kconfig
+++ b/board/buffalo/lsxl/Kconfig
@@ -9,4 +9,15 @@
 config SYS_CONFIG_NAME
 	default "lsxl"
 
+choice
+	prompt "Board model"
+
+config LSCHLV2
+	bool "LSCHLV2 support"
+
+config LSXHL
+	bool "LSXHL support"
+
+endchoice
+
 endif