Remove typedef of HMAC_CTX from crypto/hmac/hmac_lcl.h

This is already defined in include/openssl/ossl_typ.h.
Reviewed-by: NMatt Caswell <matt@openssl.org>

crypto/hmac/hmac_lcl.h

@@ -65,13 +65,13 @@ extern "C" {
 }
 #endif
 
-typedef struct hmac_ctx_st {
+struct hmac_ctx_st {
     const EVP_MD *md;
     EVP_MD_CTX *md_ctx;
     EVP_MD_CTX *i_ctx;
     EVP_MD_CTX *o_ctx;
     unsigned int key_length;
     unsigned char key[HMAC_MAX_MD_CBLOCK];
-} HMAC_CTX;
+};
 
 #endif