dm: cache: Create a uclass for cache

The cache UCLASS will be used for configure settings that can be found
in a CPU's L2 cache controller.

Add a uclass and a test for cache.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>
diff --git a/drivers/cache/Kconfig b/drivers/cache/Kconfig
new file mode 100644
index 0000000..8b7c9c7
--- /dev/null
+++ b/drivers/cache/Kconfig
@@ -0,0 +1,16 @@
+#
+# Cache controllers
+#
+
+menu "Cache Controller drivers"
+
+config CACHE
+	bool "Enable Driver Model for Cache controllers"
+	depends on DM
+	help
+	  Enable driver model for cache controllers that are found on
+	  most CPU's. Cache is memory that the CPU can access directly and
+	  is usually located on the same chip. This uclass can be used for
+	  configuring settings that be found from a device tree file.
+
+endmenu