arm64: defconfig: Enable DRM_V3D

BCM2711, the SoC used on the Raspberry Pi 4 has a different GPU than its
predecessors. Enable it.

Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Signed-off-by: Peter Robinson <pbrobinson@gmail.com>
Reviewed-by: Stefan Wahren <stefan.wahren@i2se.com>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>