Command usage cleanup

Remove command name from all command "usage" fields and update
common/command.c to display "name - usage" instead of
just "usage". Also remove newlines from command usage fields.

Signed-off-by: Peter Tyser <ptyser@xes-inc.com>
diff --git a/board/sandburst/metrobox/metrobox.c b/board/sandburst/metrobox/metrobox.c
index 19302dc..ec4c451 100644
--- a/board/sandburst/metrobox/metrobox.c
+++ b/board/sandburst/metrobox/metrobox.c
@@ -544,7 +544,7 @@
 }
 
 U_BOOT_CMD(mbsetup, 1, 1, metroboxSetupVars,
-	   "mbsetup - Set environment to factory defaults\n", NULL);
+	   "Set environment to factory defaults", NULL);
 
 U_BOOT_CMD(mbrecover, 1, 1, metroboxRecover,
-	   "mbrecover - Set environment to allow for fs recovery\n", NULL);
+	   "Set environment to allow for fs recovery", NULL);