bcm2835_rng_rust: add devicetree matching

Devices described in the devicetree with the following `compatible`
string will now match:

`brcm,bcm2835-rng`

Example devicetree .dts:

```dts
&some_bus {
        rng@7e104000 {
                compatible = "brcm,bcm2835-rng";
                reg = <0x7e104000 0x10>;
        };

        rng@7e104040 {
                compatible = "brcm,bcm2835-rng";
                reg = <0x7e104040 0x10>;
        };
};
```

This will instantiate two hardware random-number generator devices.

Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com>

Author: Sven Van Asbroeck

drivers/char/hw_random/bcm2835_rng_rust.rs

@@ -7,6 +7,7 @@
 
 use alloc::boxed::Box;
 use core::pin::Pin;
+use kernel::of::OfMatchTable;
 use kernel::prelude::*;
 use kernel::{cstr, platdev};
 
@@ -24,7 +25,13 @@ struct RngModule {
 
 impl KernelModule for RngModule {
     fn init() -> Result<Self> {
-        let pdev = platdev::Registration::new_pinned(cstr!("bcm2835-rng-rust"), &THIS_MODULE)?;
+        let of_match_tbl = OfMatchTable::new(&cstr!("brcm,bcm2835-rng"))?;
+
+        let pdev = platdev::Registration::new_pinned(
+            cstr!("bcm2835-rng-rust"),
+            Some(of_match_tbl),
+            &THIS_MODULE,
+        )?;
 
         Ok(RngModule { _pdev: pdev })
     }