remoteproc: Introduce a sandbox dummy driver

Introduce a dummy driver for sandbox that allows us to verify basic
functionality. This is not meant to do anything functional - but is
more or less meant as a framework plumbing debug helper.

The sandbox remoteproc driver maintains absolutey no states and is a
simple driver which just is filled with empty hooks. Idea being to give
an approximate idea to implement own remoteproc driver using this as a
template.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Nishanth Menon <nm@ti.com>
Acked-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/remoteproc/Kconfig b/drivers/remoteproc/Kconfig
index 4446826..437224b 100644
--- a/drivers/remoteproc/Kconfig
+++ b/drivers/remoteproc/Kconfig
@@ -12,4 +12,13 @@
 	bool
 	depends on DM
 
+# Please keep the configuration alphabetically sorted.
+config REMOTEPROC_SANDBOX
+	bool "Support for Test processor for Sandbox"
+	select REMOTEPROC
+	depends on DM
+	depends on SANDBOX
+	help
+	  Say 'y' here to add support for test processor which does dummy
+	  operations for sandbox platform.
 endmenu