Replace utils::popcnt32 with std::popcount

Cleanup includes.

Utilities/asm.h

@@ -4,23 +4,6 @@
 
 namespace utils
 {
-	inline u8 popcnt32(u32 arg)
-	{
-#ifdef _MSC_VER
-		const u32 a1 = arg & 0x55555555;
-		const u32 a2 = (arg >> 1) & 0x55555555;
-		const u32 a3 = a1 + a2;
-		const u32 b1 = a3 & 0x33333333;
-		const u32 b2 = (a3 >> 2) & 0x33333333;
-		const u32 b3 = b1 + b2;
-		const u32 c3 = (b3 + (b3 >> 4)) & 0x0f0f0f0f;
-		const u32 d3 = c3 + (c3 >> 8);
-		return static_cast<u8>(d3 + (d3 >> 16));
-#else
-		return __builtin_popcount(arg);
-#endif
-	}
-
 // Rotate helpers
 #if defined(__GNUG__)