Removed unused InitializeZero function from StandardSurface

Gems/Atom/Feature/Common/Assets/ShaderLib/Atom/Features/PBR/Surfaces/StandardSurface.azsli

@@ -32,8 +32,6 @@ class Surface
     float roughnessA;           //!< Actual roughness value ( a.k.a. "alpha roughness") to be used in microfacet calculations
     float roughnessA2;          //!< Alpha roughness ^ 2 (i.e. roughnessA * roughnessA), used in GGX, cached here for perfromance
 
-    void InitializeToZero();
-
     //! Applies specular anti-aliasing to roughnessA2 
     void ApplySpecularAA();
 
@@ -45,19 +43,6 @@ class Surface
 
 };
 
-void Surface::InitializeToZero()
-{
-    clearCoat.InitializeToZero();
-    transmission.InitializeToZero();
-    position = float3(0,0,0);
-    normal = float3(0,0,0);
-    albedo = float3(0,0,0);
-    specularF0 = float3(0,0,0);
-    roughnessLinear = 0.0f;
-    roughnessA = 0.0f;
-    roughnessA2 = 0.0f;
-}
-
 // Specular Anti-Aliasing technique from this paper:
 // http://www.jp.square-enix.com/tech/library/pdf/ImprovedGeometricSpecularAA.pdf
 void Surface::ApplySpecularAA()