sandbox: Add a new 'sb' command

The old 'sb' command was deprecated in 2015 and replaced with 'host'. It
is useful to be able to access some internal sandbox state, particularly
for testing.

Resurrect the old command and provide a way to print some basic state
information (currently just the arguments to sandbox).

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/sandbox/cpu/start.c b/arch/sandbox/cpu/start.c
index 28ca353..b1566a8 100644
--- a/arch/sandbox/cpu/start.c
+++ b/arch/sandbox/cpu/start.c
@@ -305,6 +305,16 @@
 	gd->ram_size = state->ram_size;
 }
 
+void state_show(struct sandbox_state *state)
+{
+	char **p;
+
+	printf("Arguments:\n");
+	for (p = state->argv; *p; p++)
+		printf("%s ", *p);
+	printf("\n");
+}
+
 int main(int argc, char *argv[])
 {
 	struct sandbox_state *state;