Determine the framebuffer format from the fb0 device. Bug 25390254 Change-Id: I21ed5b6d4a918bb6c3ac9ccc31ee5d47e193bd7f Reviewed-on: https://swiftshader-review.googlesource.com/4184 Reviewed-by: Alexis Hétu <sugoi@google.com> Tested-by: Nicolas Capens <capn@google.com> Reviewed-by: Nicolas Capens <capn@google.com>