gpu: nova-core: take bound device in Gpu::new

We will need to perform things like allocating DMA memory during device
creation, so make sure to take the device context that will allow us to
perform these actions. This also allows us to use Devres::access to
obtain the BAR without holding a RCU lock.

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Link: https://lore.kernel.org/r/20250507-nova-frts-v3-4-fcb02749754d@nvidia.com


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