cros_ec: Support the full-size vboot context

The v2 format is 64-bytes in size. Support this and drop v1 since it is
not used anymore.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/misc/cros_ec_sandbox.c b/drivers/misc/cros_ec_sandbox.c
index ab91f3f..12cc11e 100644
--- a/drivers/misc/cros_ec_sandbox.c
+++ b/drivers/misc/cros_ec_sandbox.c
@@ -343,15 +343,13 @@
 
 		switch (req->op) {
 		case EC_VBNV_CONTEXT_OP_READ:
-			/* TODO(sjg@chromium.org): Support full-size context */
 			memcpy(resp->block, ec->vbnv_context,
-			       EC_VBNV_BLOCK_SIZE);
-			len = 16;
+			       EC_VBNV_BLOCK_SIZE_V2);
+			len = EC_VBNV_BLOCK_SIZE_V2;
 			break;
 		case EC_VBNV_CONTEXT_OP_WRITE:
-			/* TODO(sjg@chromium.org): Support full-size context */
 			memcpy(ec->vbnv_context, req->block,
-			       EC_VBNV_BLOCK_SIZE);
+			       EC_VBNV_BLOCK_SIZE_V2);
 			len = 0;
 			break;
 		default: