[nbdd0121]

Use let mut for created bindings of initialized field, so Pin<&mut T> bindings may be reborrowed in subsequent initializers or code blocks.

Without let mut, attempt to reborrow can produce error (and also a confusing fix):

error[E0596]: cannot borrow `gpu` as mutable, as it is not declared as mutable
   --> drivers/gpu/nova-core/driver.rs:129:17
    |
129 |                 gpu.as_mut().run_selftests(pdev);
    |                 ^^^ cannot borrow as mutable
    |
help: consider changing this to be mutable                                                                                                                                                                                  |
119 |             mut gpu <- Gpu::new(
    |             +++

error: aborting due to 1 previous error

Reported-by: Danilo Krummrich dakr@kernel.org