sizeof() updated to cover coding style

Reviewed-by: NRichard Levitte <levitte@openssl.org>
Reviewed-by: NRich Salz <rsalz@openssl.org>

crypto/bio/bss_mem.c

@@ -139,13 +139,13 @@ BIO *BIO_new_mem_buf(const void *buf, int len)
 
 static int mem_init(BIO *bi, unsigned long flags)
 {
-    BIO_BUF_MEM *bb = OPENSSL_zalloc(sizeof(BIO_BUF_MEM));
+    BIO_BUF_MEM *bb = OPENSSL_zalloc(sizeof(*bb));
 
     if (bb == NULL)
         return(0);
     if ((bb->buf = BUF_MEM_new_ex(flags)) == NULL)
         return(0);
-    if ((bb->readp = OPENSSL_zalloc(sizeof(BUF_MEM))) == NULL)
+    if ((bb->readp = OPENSSL_zalloc(sizeof(*bb->readp))) == NULL)
         return(0);
     *bb->readp = *bb->buf;
     bi->shutdown = 1;