Fix returning value for uw_crypto_hmac_init_

Change-Id: I5f4c68fb5ca96d3c7db3e4760473837a130bbf66
Reviewed-on: https://weave-review.googlesource.com/1861
Reviewed-by: Vitaly Buka <vitalybuka@google.com>
diff --git a/third_party/libuweave/src/crypto_hmac.c b/third_party/libuweave/src/crypto_hmac.c
index 56bb754..8b75133 100644
--- a/third_party/libuweave/src/crypto_hmac.c
+++ b/third_party/libuweave/src/crypto_hmac.c
@@ -24,7 +24,7 @@
   }
   HMAC_CTX* context = (HMAC_CTX*)state_buffer;
   HMAC_CTX_init(context);
-  return HMAC_Init(context, key, key_len, EVP_sha256()) ? 0 : sizeof(HMAC_CTX);
+  return HMAC_Init(context, key, key_len, EVP_sha256());
 }
 
 bool uw_crypto_hmac_update_(uint8_t* state_buffer,