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/pxa255_idp/pxa_idp.c b/board/pxa255_idp/pxa_idp.c
index b0aa8dd..aa598aa 100644
--- a/board/pxa255_idp/pxa_idp.c
+++ b/board/pxa255_idp/pxa_idp.c
@@ -128,7 +128,7 @@
 }
 
 U_BOOT_CMD(idpcmd, CONFIG_SYS_MAXARGS, 0, do_idpcmd,
-	   "idpcmd    - custom IDP command\n",
+	   "custom IDP command",
 	   "no args at this time\n"
 );