rust: Update PCI binding safety comments and add inline compiler hint

rust: Update PCI binding safety comments and add inline compiler hint

Update the safety comments to be consistent with other safety comments
in the PCI bindings. Also add an inline compiler hint.

Suggested-by: Danilo Krummrich <dakr@kernel.org>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Krzysztof Wilczyński <kwilczynski@kernel.org>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Alex Gaynor <alex.gaynor@gmail.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Gary Guo <gary@garyguo.net>
Cc: Björn Roy Baron <bjorn3_gh@protonmail.com>
Cc: Benno Lossin <lossin@kernel.org>
Cc: Andreas Hindborg <a.hindborg@kernel.org>
Cc: Alice Ryhl <aliceryhl@google.com>
Cc: Trevor Gross <tmgross@umich.edu>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Rafael J. Wysocki <rafael@kernel.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Alexandre Courbot <acourbot@nvidia.com>
Cc: linux-pci@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Link: https://lore.kernel.org/r/20250730013417.640593-1-apopple@nvidia.com
Signed-off-by: Danilo Krummrich <dakr@kernel.org>