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/README b/README
index afcc671..86c1304 100644
--- a/README
+++ b/README
@@ -2045,6 +2045,9 @@
 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
 		undefine this when you're short of memory.
 
+- CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
+		width of the commands listed in the 'help' command output.
+
 - CONFIG_SYS_PROMPT:	This is what U-Boot prints on the console to
 		prompt for user input.