rust: serdev: use ThisModule::as_ptr() instead of field access

The THIS_MODULE series [1] applied to rust-next moved ThisModule from
lib.rs into a module.rs submodule, making the tuple struct field private
outside the module. This breaks the module.0 field access in serdev in
driver-core-next.

Update the call to __serdev_device_driver_register() to use the public
module.as_ptr() accessor to fix the build.

Link: https://lore.kernel.org/all/20260811-fix-fops-owner-v10-0-7e71776f9dbe@linux.dev/ [1]
Closes: https://lore.kernel.org/all/DKNAS52KYWLD.M15VEC6U0F6R@kernel.org/
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Markus Probst <markus.probst@posteo.de>
Link: https://patch.msgid.link/20260813152444.514580-1-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>

rust/kernel/serdev.rs

@@ -87,7 +87,7 @@ unsafe impl<T: Driver> driver::RegistrationOps for Adapter<T> {
         }
 
         // SAFETY: `sdrv` is guaranteed to be a valid `DriverType`.
-        to_result(unsafe { bindings::__serdev_device_driver_register(sdrv.get(), module.0) })
+        to_result(unsafe { bindings::__serdev_device_driver_register(sdrv.get(), module.as_ptr()) })
     }
 
     unsafe fn unregister(sdrv: &Opaque<Self::DriverType>) {