Simplify away the passed pawn extension

Simplify away the passed pawn extension

STC https://tests.stockfishchess.org/tests/view/5f3955f0e98b6c64b3df41d7
LLR: 2.96 (-2.94,2.94) {-1.50,0.50}
Total: 31992 W: 3611 L: 3548 D: 24833
Ptnml(0-2): 174, 2658, 10273, 2713, 178

LTC https://tests.stockfishchess.org/tests/view/5f399e41e98b6c64b3df4210
LLR: 3.01 (-2.94,2.94) {-1.50,0.50}
Total: 29568 W: 1488 L: 1480 D: 26600
Ptnml(0-2): 40, 1272, 12142, 1300, 30

closes https://github.com/official-stockfish/Stockfish/pull/3017

bench: 3844671

-----

Recommended net: https://tests.stockfishchess.org/api/nn/nn-82215d0fd0df.nnue