Standardize command usage messages with cmd_usage()

Signed-off-by: Peter Tyser <ptyser@xes-inc.com>
diff --git a/board/amcc/acadia/cmd_acadia.c b/board/amcc/acadia/cmd_acadia.c
index 052cf61..9fc03f1 100644
--- a/board/amcc/acadia/cmd_acadia.c
+++ b/board/amcc/acadia/cmd_acadia.c
@@ -45,7 +45,7 @@
 	int cpu_freq;
 
 	if (argc < 3) {
-		printf("Usage:\n%s\n", cmdtp->usage);
+		cmd_usage(cmdtp);
 		return 1;
 	}