Fix clippy::needless_option_as_deref complaint
Despite what clippy says we can't just drop `.as_deref_mut()` because we need `free` to be `mut`.
Change to `as_mut()` and everything should be fine.
@@ -221,7 +221,7 @@ impl RwLocked<HostMap> {
// we have reached the end of the free slot page
// advance to the next page
- if let Some(f) = free.header.next {
+ if let Some(f) = free.header.next.as_mut() {
free = f;
} else {
return None;
