gpu: nova-core: select AUXILIARY_BUS instead of depending on it

CONFIG_AUXILIARY_BUS cannot be enabled explicitly, and unless we select
it we have no way to include it (and thus to enable NOVA_CORE) unless
another driver happens to do it for us.

Fixes: e041d81a ("gpu: nova-core: register auxiliary device for nova-drm")
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Link: https://lore.kernel.org/r/20250515-aux_bus-v2-2-47c70f96ae9b@nvidia.com


Signed-off-by: Danilo Krummrich <dakr@kernel.org>