BoringSSL: Define RSA_bits() helper

It looks like BoringSSL claims to have OPENSSL_VERSION_NUMBER for a
1.1.0 version, but it does not provide RSA_bits(). For now, add this
backwards compatibility wrapper for BoringSSL regardless of the version
it claims to be.

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>

src/crypto/tls_openssl.c

@@ -103,7 +103,7 @@ static size_t SSL_SESSION_get_master_key(const SSL_SESSION *session,
 
 #endif
 
-#if OPENSSL_VERSION_NUMBER < 0x10100000L
+#if OPENSSL_VERSION_NUMBER < 0x10100000L || defined(OPENSSL_IS_BORINGSSL)
 #ifdef CONFIG_SUITEB
 static int RSA_bits(const RSA *r)
 {