Split LK fastboot into a separate script

Refactor the flash.sh script based on feedback

To flash the board with LK fastboot implementation, the user needs to
run enable_lk_fastboot.sh first

The new scripts still supports different directory location and EVT1
board.

Change-Id: I78aa95cf789e891ccc2b11a1fc8d0fba62505c38
2 files changed