bcm: don't forget to cleanup HMAC_CTX.

(HMAC_CTXs have interior allocations.)

Change-Id: Ic0e67cf9c52db43e895088e602079c510bb8432a
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/36284
Reviewed-by: Adam Langley <agl@google.com>
Commit-Queue: Adam Langley <agl@google.com>
diff --git a/crypto/fipsmodule/bcm.c b/crypto/fipsmodule/bcm.c
index 64a320d..3fad74b 100644
--- a/crypto/fipsmodule/bcm.c
+++ b/crypto/fipsmodule/bcm.c
@@ -153,6 +153,7 @@
     fprintf(stderr, "HMAC failed.\n");
     goto err;
   }
+  HMAC_CTX_cleanup(&hmac_ctx);
 
   const uint8_t *expected = BORINGSSL_bcm_text_hash;