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/delta/delta.c b/board/delta/delta.c
index 878416f..73e6c3e 100644
--- a/board/delta/delta.c
+++ b/board/delta/delta.c
@@ -259,7 +259,7 @@
 
 U_BOOT_CMD(
 	   kbd,	1,	1,	do_kbd,
-	   "kbd     - read keyboard status\n",
+	   "read keyboard status",
 	   NULL
 );