Fix for display corruption on GLK19264A

In some cases, the set and save brightness command would cause corruption on the GLK19264A USB display (see picture), changing to set brightness without saving command.

![2014-11-24 15 53 13](https://cloud.githubusercontent.com/assets/3372394/5182871/cdadb44e-749f-11e4-81cc-f2c7efe41c96.jpg)