Fix alpha value for device orientation

This seems to have been incorrect since this code was first written for HC. I
can only think that the error was made due to confusion between portrait and
landscape mode as development switched from phones to tablets.

Tested on stingray and prime.

A similar fix will be required for Chrome.

Change-Id: I5da13c489fdb9de340b9e6ea8868c9f1adc15bb2