TLB cache fixes

Updated C bit on TLB cache hits.
Added TLB state to the save state file.
Removed the tag check in InvalidateTLBEntry. All four TLB entries are always cleared on each invalidate command.
Initialised the TLB cache to start from a consistent state on reset.


If updating the C bit directly doesn't work it's a good indicator that something else is wrong and a full copy of the PTE should be kept in the TLB rather than just a PTE pointer.
It also looks like there's the possibility that both TLB ways (tlbe[0] and tlbe[1]) can end up caching the same address since UpdateTLBEntry() does nothing to prevent it happening.