Remove SelectAll::into_inner.

Due to not requiring Unpin, it's not really possible to call it
after having polled it, you can only call it right after constructing it,
so in practice it's not very useful.

embassy/src/util/select.rs

@@ -25,13 +25,6 @@ pub fn select_all<Fut: Future, const N: usize>(arr: [Fut; N]) -> SelectAll<Fut,
     SelectAll { inner: arr }
 }
 
-impl<Fut, const N: usize> SelectAll<Fut, N> {
-    /// Consumes this combinator, returning the underlying futures.
-    pub fn into_inner(self) -> [Fut; N] {
-        self.inner
-    }
-}
-
 impl<Fut: Future, const N: usize> Future for SelectAll<Fut, N> {
     type Output = (Fut::Output, usize);