virtio-gpu: disable VIRGL with BE kernel

VIRTIO_GPU_F_VIRGL is added in features list only
for LE kernel, so we must check for it only on LE kernel,
otherwise virtio_has_feature() calls BUG() and
crashes the kernel.

Suggested-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1485263549-28743-1-git-send-email-lvivier@redhat.com


Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>