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/cpu/mpc83xx/speed.c b/cpu/mpc83xx/speed.c
index 4230099..9b7e7b5 100644
--- a/cpu/mpc83xx/speed.c
+++ b/cpu/mpc83xx/speed.c
@@ -544,6 +544,6 @@
 }
 
 U_BOOT_CMD(clocks, 1, 0, do_clocks,
-	"clocks  - print clock configuration\n",
+	"print clock configuration",
 	"    clocks\n"
 );