spl: Add support for passing handoff info to U-Boot proper

There is some basic informaton that SPL normally wants to pass through to
U-Boot, such as the SDRAM size and bank information.

Mkae use of the new bloblist structure for this. Add a new 'handoff' blob
which is set up in SPL and passed to U-Boot proper. Also adda  test for
sandbox_spl that checks that this works correctly and a new 'sb' command
to show the information passed from SPL.

Reviewed-by: Tom Rini <trini@konsulko.com>
Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/test/run b/test/run
index fb8ff5d..cd323b0 100755
--- a/test/run
+++ b/test/run
@@ -19,7 +19,7 @@
 
 # Run tests which require sandbox_spl
 run_test "sandbox_spl" ./test/py/test.py --bd sandbox_spl --build \
-	-k test_ofplatdata.py
+	-k 'test_ofplatdata or test_handoff'
 
 # Run tests for the flat-device-tree version of sandbox. This is a special
 # build which does not enable CONFIG_OF_LIVE for the live device tree, so we can