libEGL: use s/w rendering on h/w with no GPU

Fallback to Software Renderer used for emulators if we are running
on a hardware with no GPU support.

Change-Id: Id0772f466b5a08f90e7f9eceeb9b8f5f69179539
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
(cherry picked from commit 625cb94919181e6c798171990bb3dc157d83f068)