Drop not defended by pawn condition

Passed no-regression test both at STC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 96554 W: 17563 L: 17572 D: 61419

and at LTC
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 31891 W: 4905 L: 4801 D: 22185

bench: 7720896

src/evaluate.cpp

@@ -204,8 +204,6 @@ namespace {
   const int BishopCheck       = 2;
   const int KnightCheck       = 3;
 
-  const int UnsupportedPinnedPiece = 2;
-
   // KingDanger[Color][attackUnits] contains the actual king danger weighted
   // scores, indexed by color and by a calculated integer number.
   Score KingDanger[COLOR_NB][128];
@@ -631,6 +629,7 @@ Value do_evaluate(const Position& pos) {
         // the pawn shelter (current 'score' value).
         attackUnits =  std::min(20, (ei.kingAttackersCount[Them] * ei.kingAttackersWeight[Them]) / 2)
                      + 3 * (ei.kingAdjacentZoneAttacksCount[Them] + popcount<Max15>(undefended))
+                     + 2 * (ei.pinnedPieces[Us] != 0)
                      - mg_value(score) / 32;
 
         // Analyse the enemy's safe queen contact checks. Firstly, find the
@@ -695,10 +694,6 @@ Value do_evaluate(const Position& pos) {
         if (b)
             attackUnits += KnightCheck * popcount<Max15>(b);
 
-        // Penalty for pinned pieces not defended by a pawn
-        if (ei.pinnedPieces[Us] & ~ei.attackedBy[Us][PAWN])
-            attackUnits += UnsupportedPinnedPiece;
-
         // To index KingDanger[] attackUnits must be in [0, 99] range
         attackUnits = std::min(99, std::max(0, attackUnits));