Do preventDefault on focus and keydown event in enyo.input

Problem:
If input field is focused or get key event while it is at outside of screen,
browser is re-positioning whole content which is including input into the screen.
This happens even if body has overflow: hidden on it.

Fix:
Do preventDefault on focus and keydown event to prevent browser's behavior
while it is at outside of screen.

Fixing http://jira2.lgsvl.com/browse/BHV-11008

DCO-1.1-Signed-Off-By: Kunmyon Choi kunmyon.choi@lge.com