Simplify material difference in evaluate

Simplify material difference in evaluate

STC: https://tests.stockfishchess.org/tests/view/64d166235b17f7c21c0ddc15
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 100032 W: 25698 L: 25547 D: 48787
Ptnml(0-2): 308, 11748, 25771, 11863, 326

LTC: https://tests.stockfishchess.org/tests/view/64d28c085b17f7c21c0df775
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 123870 W: 31463 L: 31348 D: 61059
Ptnml(0-2): 63, 13487, 34719, 13604, 62

Besides rebasing I replaced PawnValueMg w/ 126 explicitly to decouple from https://tests.stockfishchess.org/tests/view/64d212de5b17f7c21c0debbb by @peregrineshahin which also passed. #4734

closes https://github.com/official-stockfish/Stockfish/pull/4731

Bench: 1447866