Remove free(self) in HMAC which goes against esp-hal API guidelines

esp-hal/CHANGELOG.md

@@ -25,6 +25,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - DMA buffers now don't require a static lifetime. Make sure to never `mem::forget` an in-progress DMA transfer (consider using `#[deny(clippy::mem_forget)]`) (#1837)
 - Peripherals (where possible) are now explicitly reset and enabled in their constructors (#1893)
 - Reset peripherals in driver constructors where missing (#1893, #1961)
+- Remove `fn free(self)` in HMAC which goes against esp-hal API guidelines (#1972)
 
 ### Fixed
 

esp-hal/src/hmac.rs

@@ -109,10 +109,6 @@ impl<'d> Hmac<'d> {
         }
     }
 
-    pub fn free(self) -> PeripheralRef<'d, HMAC> {
-        self.hmac
-    }
-
     /// Step 1. Enable HMAC module.
     ///
     /// Before these steps, the user shall set the peripheral clocks bits for