rust: miscdevice: fix typo in MiscDevice::ioctl documentation

rust: miscdevice: fix typo in MiscDevice::ioctl documentation

Fixes one small typo (`utilties` to `utilities`) in the documentation of
`MiscDevice::ioctl`.

Fixes: f893691e7426 ("rust: miscdevice: add base miscdevice abstraction")
Signed-off-by: Christian Schrefl <chrisi.schrefl@gmail.com>
Reviewed-by: Benno Lossin <lossin@kernel.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20250517-rust_miscdevice_fix_typo-v1-1-8c30a6237ba9@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>