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/lcd.c b/common/lcd.c
index ae79051..5f73247 100644
--- a/common/lcd.c
+++ b/common/lcd.c
@@ -426,7 +426,7 @@
 
 U_BOOT_CMD(
 	cls,	1,	1,	lcd_clear,
-	"cls     - clear screen\n",
+	"clear screen",
 	NULL
 );