Update number of SSS profile to 16

ScriptableRenderPipeline/HDRenderPipeline/Material/Lit/SubsurfaceScatteringSettings.cs

     [GenerateHLSL]
     public class SssConstants
     {
-        public const int SSS_N_PROFILES           = 8;  // Max. number of profiles, including the slot taken by the neutral profile
+        public const int SSS_N_PROFILES           = 16;  // Max. number of profiles, including the slot taken by the neutral profile
         public const int SSS_NEUTRAL_PROFILE_ID   = SSS_N_PROFILES - 1; // Does not result in blurring
         public const int SSS_N_SAMPLES_NEAR_FIELD = 55; // Used for extreme close ups; must be a Fibonacci number
         public const int SSS_N_SAMPLES_FAR_FIELD  = 21; // Used at a regular distance; must be a Fibonacci number

ScriptableRenderPipeline/HDRenderPipeline/Material/Lit/SubsurfaceScatteringSettings.cs.hlsl

 //
 // UnityEngine.Experimental.Rendering.HDPipeline.SssConstants:  static fields
 //
-#define SSS_N_PROFILES (8)
-#define SSS_NEUTRAL_PROFILE_ID (7)
+#define SSS_N_PROFILES (16)
+#define SSS_NEUTRAL_PROFILE_ID (15)
 #define SSS_N_SAMPLES_NEAR_FIELD (55)
 #define SSS_N_SAMPLES_FAR_FIELD (21)
 #define SSS_LOD_THRESHOLD (4)