Add the BitFieldInsert() intrinsic

ScriptableRenderPipeline/Core/ShaderLibrary/API/PSSL.hlsl

 #define BitFieldExtract __v_bfe_u32
 #define INTRINSIC_BITFIELD_EXTRACT_SIGN_EXTEND
 #define BitFieldExtractSignExtend __v_bfe_i32
+#define INTRINSIC_BITFIELD_INSERT
+#define BitFieldInsert __v_bfi_b32
 #define INTRINSIC_WAVEREADFIRSTLANE
 #define WaveReadFirstLane ReadFirstLane
 #define INTRINSIC_MAD24

ScriptableRenderPipeline/Core/ShaderLibrary/Common.hlsl

 }
 #endif // INTRINSIC_BITFIELD_EXTRACT_SIGN_EXTEND
 
+#ifdef INTRINSIC_BITFIELD_INSERT
+// Inserts the bits indicated by 'mask' from 'src' into 'dst'.
+uint BitFieldInsert(uint mask, uint src, uint dst)
+{
+    return (src & mask) | (dst & ~mask);
+}
+#endif // INTRINSIC_BITFIELD_INSERT
+
 bool IsBitSet(uint data, uint offset)
 {
     return BitFieldExtract(data, offset, 1u) != 0;