drm/gma500: Add compat ioctl

Hook up drm_compat_ioctl to support 32-bit userspace on 64-bit kernels.
It turns out that N2600 and N2800 comes with 64-bit enabled. We
previously assumed there where no such systems out there.

Cc: stable@vger.kernel.org
Signed-off-by: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: http://patchwork.freedesktop.org/patch/msgid/20161101144315.2955-1-patrik.r.jakobsson@gmail.com

drivers/gpu/drm/gma500/psb_drv.c

@@ -473,6 +473,9 @@ static const struct file_operations psb_gem_fops = {
 	.open = drm_open,
 	.release = drm_release,
 	.unlocked_ioctl = psb_unlocked_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl = drm_compat_ioctl,
+#endif
 	.mmap = drm_gem_mmap,
 	.poll = drm_poll,
 	.read = drm_read,