gpu: nova-core: store Fsp instance in Gpu
The `Fsp` instance was only used in the Hopper+ boot path, and consequently built locally (and immediately dropped) in it. This worked well as a temporary measure, but the FSP is a GPU sub-device, so its lifetime should match the GPU rather than a single boot invocation. It will also be needed in other parts of the driver, for instance vGPU. Thus, create the `Fsp` instance in the `Gpu` constructor and store it there, passing it to the GSP boot as a mutable reference using `GspBootContext`. This makes the `Fsp` available even after the GSP is booted. Reviewed-by: Eliot Courtney <ecourtney@nvidia.com> Link: https://patch.msgid.link/20260709-nova-bootcontext-v6-13-520cbf8b9b50@nvidia.com Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>