RT 1988: Add "const" to SSL_use_RSAPrivateKey_ASN1

The "unsigned char *d" should be const.
Reviewed-by: Kurt Roeckx <kurt@roeckx.be>
diff --git a/ssl/ssl_rsa.c b/ssl/ssl_rsa.c
index 7c02878..c76a2a3 100644
--- a/ssl/ssl_rsa.c
+++ b/ssl/ssl_rsa.c
@@ -296,7 +296,7 @@
 	}
 #endif
 
-int SSL_use_RSAPrivateKey_ASN1(SSL *ssl, unsigned char *d, long len)
+int SSL_use_RSAPrivateKey_ASN1(SSL *ssl, const unsigned char *d, long len)
 	{
 	int ret;
 	const unsigned char *p;