Fix or silence clippy warnings on nightly

Fix:
- dead_code
- clippy::if_then_panic
- clippy::manual_memcpy
- clippy::needless_borrow

Silence:
- clippy::missing_safety_doc
- clippy::needless_range_loop
- clippy::single_match

Signed-off-by: Tim Crawford <tcrawford@system76.com>

tool/src/access/hid.rs

@@ -40,9 +40,7 @@ impl AccessHid {
         }
 
         hid_data[HID_CMD] = cmd;
-        for i in 0..data.len() {
-            hid_data[HID_DATA + i] = data[i];
-        }
+        hid_data[HID_DATA..(data.len() + HID_DATA)].clone_from_slice(data);
 
         let count = self.device.write(&hid_data)?;
         if count != hid_data.len() {
@@ -51,9 +49,7 @@ impl AccessHid {
 
         let count = self.device.read_timeout(&mut hid_data[1..], self.timeout)?;
         if count == hid_data.len() - 1 {
-            for i in 0..data.len() {
-                data[i] = hid_data[HID_DATA + i];
-            }
+            data.clone_from_slice(&hid_data[HID_DATA..(data.len() + HID_DATA)]);
 
             Ok(Some(hid_data[HID_RES]))
         } else if count == 0 {

tool/src/access/lpc/mod.rs

@@ -4,6 +4,7 @@ const SMFI_CMD_BASE: u16 = 0xE00;
 const SMFI_CMD_SIZE: usize = 0x100;
 
 const SMFI_DBG_BASE: u16 = 0xF00;
+#[cfg(all(feature = "std", target_os = "linux"))]
 const SMFI_DBG_SIZE: usize = 0x100;
 
 const SMFI_CMD_CMD: u8 = 0x00;