Make sure a socklen_t can compare with a sizeof() result

Most of the times, it seems that socklen_t is unsigned.
Unfortunately, this isn't always the case, and it doesn't compare with
a size_t without warning.

A cast resolves the issue.
Reviewed-by: NKurt Roeckx <kurt@openssl.org>

crypto/bio/b_sock.c

@@ -432,7 +432,7 @@ int BIO_sock_info(int sock,
                 BIOerr(BIO_F_BIO_SOCK_INFO, BIO_R_GETSOCKNAME_ERROR);
                 return 0;
             }
-            if (addr_len > sizeof(*info->addr)) {
+            if ((size_t)addr_len > sizeof(*info->addr)) {
                 BIOerr(BIO_F_BIO_SOCK_INFO, BIO_R_GETSOCKNAME_TRUNCATED_ADDRESS);
                 return 0;
             }