- implement "used" bit in tlb translation entry
- mark tlb entry used if qemu code/data translation succeeds
- fold i/d mmu replacement writes code into replace_tlb_1bit_lru which
adds 1bit lru replacement algorithm; previously code tried to replace
first unlocked entry only

- extract more bitmasks to named macros
- add "immu" or "dmmu" type name to debugging output where appropriate

Signed-off-by:  <igor.v.kovalenko@gmail.com>

--
Kind regards,
Igor V. Kovalenko