net_tulip.c: Code style changes (part 1)

src/network/net_tulip.c

@@ -747,10 +747,8 @@ static uint32_t tulip_read(uint32_t addr, void *opaque)
         break;
 
     default:
-        if (addr & 7) {
+        if (!(addr & 7))
-        } else {
             data = s->csr[addr >> 3];
-        }
         break;
     }
     return data;