Simplify histories movepick formula

Simplify histories movepick formula

Passed STC:
LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 81440 W: 21100 L: 20929 D: 39411
Ptnml(0-2): 248, 9659, 20718, 9864, 231
https://tests.stockfishchess.org/tests/view/6659a8b7ea624d64ea5f3208

Passed LTC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 85758 W: 21763 L: 21607 D: 42388
Ptnml(0-2): 34, 9606, 23463, 9722, 54
https://tests.stockfishchess.org/tests/view/6659d7bff426908fcc6b692c

closes https://github.com/official-stockfish/Stockfish/pull/5326

bench: 1280472