Work around missing BGRA texture format on Samsung Galaxy Tab 3

The GL driver on the Galaxy Tab 3 reports support for the BGRA8888
texture format, but does not actually support it. For this particular
device we disable support for that format.

Task-number: QTBUG-34984
Change-Id: Ie26ef0e815c1622b3425c37237a3fc320543b92c
Reviewed-by: Gunnar Sletta <gunnar.sletta@jollamobile.com>