Add support for legacy grayscale cookies as a checkbox in the asset. Turning this on makes default spot attenutation mirror builtin

Assets/ScriptableRenderPipeline/MobileRenderPipeline/ClassicDeferred/ClassicDeferredPipeline.cs

 
 	[SerializeField]
 	TextureSettings m_TextureSettings = TextureSettings.Default;
+	public bool UseLegacyCookies;
 	public Mesh m_PointLightMesh;
 	public float PointLightMeshScaleFactor = 2.0f;
 	public Mesh m_SpotLightMesh;
 			int shadowIdx;
 			float lightShadowNDXOrNot = m_ShadowIndices.TryGetValue( (int) lightNum, out shadowIdx ) ? (float) shadowIdx : -1.0f;
 			props.SetFloat ("_LightIndexForShadowMatrixArray", lightShadowNDXOrNot);
+			props.SetFloat ("_useLegacyCookies", UseLegacyCookies?1.0f:0.0f);
 
 			Texture cookie = light.light.cookie;
 			if (cookie != null)
 		cmd.SetGlobalTexture("_reflRootCubeTexture", topCube);
 		cmd.SetGlobalFloat("_reflRootHdrDecodeMult", defdecode.x);
 		cmd.SetGlobalFloat("_reflRootHdrDecodeExp", defdecode.y);
+
+		cmd.SetGlobalFloat ("_useLegacyCookies", UseLegacyCookies?1.0f:0.0f);
 
 		context.ExecuteCommandBuffer(cmd);
 		cmd.Dispose();

Assets/ScriptableRenderPipeline/MobileRenderPipeline/ClassicDeferred/LightingTemplate.hlsl

 static float4 debugLighting;
 
 int _LightIndexForShadowMatrixArray;
+int _useLegacyCookies;
 
 void OnChipDeferredCalculateLightParams (
 	unity_v2f_deferred i,
 		
 		float4 uvCookie = mul (unity_WorldToLight, float4(wpos,1));
 		colorCookie = tex2Dlod (_LightTexture0, float4(uvCookie.xy / uvCookie.w, 0, 0));
+		[branch]if (_useLegacyCookies) {
+			colorCookie.xyz = 1;
+		}
+
 		float atten = colorCookie.w;
 		atten *= uvCookie.w < 0;
 
 
 		#if defined (DIRECTIONAL_COOKIE)
 		colorCookie = tex2Dlod (_LightTexture0, float4(mul(unity_WorldToLight, half4(wpos,1)).xy, 0, 0));
+		[branch]if (_useLegacyCookies) {
+			colorCookie.xyz = 1;
+		}
 		atten *= colorCookie.w;
 		#endif //DIRECTIONAL_COOKIE
 
 
 		#if defined (POINT_COOKIE)
 			colorCookie = texCUBElod(_LightTexture0, float4(mul(unity_WorldToLight, float4(wpos,1)).xyz, 0));
+			[branch]if (_useLegacyCookies) {
+				colorCookie.xyz = 1;
+			}
 			atten *= colorCookie.w;
 		#endif //POINT_COOKIE	
 	#else

Assets/ScriptableRenderPipeline/MobileRenderPipeline/ClassicDeferred/UnityStandardForwardMobile.cginc

 
 int g_numLights;
 int g_numReflectionProbes;
+int _useLegacyCookies;
 
 float4x4 g_mViewToWorld;
 float4x4 g_mWorldToView;        // used for reflection only
             [branch]if(bHasCookie)
             {
                angularAtt = UNITY_SAMPLE_TEX2DARRAY_LOD(_spotCookieTextures, float3(cookCoord, gPerLightData[lightIndex].z), 0.0);
+            }
+            [branch]if(_useLegacyCookies)
+            {
+            	angularAtt.xyz = 1;
             }
             atten *= angularAtt.w*(-uvCookie.w>0.0);                           // finally apply this to the dist att.
 

Assets/TestScenes/MobileDeferredTest/ClassicDeferredPipeline.asset

     spotCookieSize: 512
     pointCookieSize: 128
     reflectionCubemapSize: 128
+  UseLegacyCookies: 1
   m_PointLightMesh: {fileID: 10207, guid: 0000000000000000e000000000000000, type: 0}
   PointLightMeshScaleFactor: 2
   m_SpotLightMesh: {fileID: 4300000, guid: 93e85ba57f65145538a8ac97bd005d40, type: 3}