mako: Cleanup device.mk

PS 1-3
* delete obsolete entries
* don't copy items already copied by build

PS 4
* remove persist.sys.usb.config override
  The variable persist.sys.usb.config is no longer honored by the framework,
  and it's presence causes unnecessary toggling of the USB driver, which
  disonnects ADB and makes the device's connection unstable.

Change-Id: I0fc3c4c2cc0da71b6679032a515f3549bd17d63c