Standardize command usage messages with cmd_usage()

Signed-off-by: Peter Tyser <ptyser@xes-inc.com>
diff --git a/common/cmd_dcr.c b/common/cmd_dcr.c
index 439d07a..7d382bb 100644
--- a/common/cmd_dcr.c
+++ b/common/cmd_dcr.c
@@ -45,7 +45,7 @@
 
 	/* Validate arguments */
 	if (argc < 2) {
-		printf ("Usage:\n%s\n", cmdtp->usage);
+		cmd_usage(cmdtp);
 		return 1;
 	}
 
@@ -74,7 +74,7 @@
 
 	/* Validate arguments */
 	if (argc < 2) {
-		printf ("Usage:\n%s\n", cmdtp->usage);
+		cmd_usage(cmdtp);
 		return 1;
 	}
 
@@ -121,7 +121,7 @@
 
 	/* Validate arguments */
 	if (argc < 3) {
-		printf ("Usage:\n%s\n", cmdtp->usage);
+		cmd_usage(cmdtp);
 		return 1;
 	}
 
@@ -177,7 +177,7 @@
 
 	/* Validate arguments */
 	if (argc < 4) {
-		printf ("Usage:\n%s\n", cmdtp->usage);
+		cmd_usage(cmdtp);
 		return 1;
 	}