Silence warnings about unused methods in provided drivers.

src/exercises/bare-metal/rtc/src/gicv3.rs

@@ -12,6 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+#![allow(unused)]
+
 use bitflags::bitflags;
 use core::{
     arch::asm,

src/exercises/bare-metal/rtc/src/pl011.rs

@@ -12,6 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+#![allow(unused)]
+
 use core::fmt::{self, Write};
 use core::ptr::{addr_of, addr_of_mut};