Mem: Fix incorrect logic in bus blocksize check

This patch fixes the logic in the blocksize check such that the
warning is printed if the size is not 16, 32, 64 or 128.

src/mem/bus.cc

@@ -100,8 +100,8 @@ BaseBus::init()
         blockSize = peer_block_size;
 
     // check if the block size is a value known to work
-    if (blockSize != 16 || blockSize != 32 || blockSize != 64 ||
-        blockSize != 128)
+    if (!(blockSize == 16 || blockSize == 32 || blockSize == 64 ||
+          blockSize == 128))
         warn_once("Block size is neither 16, 32, 64 or 128 bytes.\n");
 }