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/common/cmd_terminal.c b/common/cmd_terminal.c
index 67a2546..fd3dd48 100644
--- a/common/cmd_terminal.c
+++ b/common/cmd_terminal.c
@@ -87,6 +87,6 @@
 
 U_BOOT_CMD(
 	terminal,	3,	1,	do_terminal,
-	"terminal - start terminal emulator\n",
+	"start terminal emulator",
 	""
 );