X86: Use the AddrTrie class to implement the TLB.

X86: Use the AddrTrie class to implement the TLB.

This change also adjusts the TlbEntry class so that it stores the number of
address bits wide a page is rather than its size in bytes. In other words,
instead of storing 4K for a 4K page, it stores 12. 12 is easy to turn into 4K,
but it's a little harder going the other way.