Stencil Payload fix for DualSourceBlendRTWrite in e64

In e64b mode, the data type for the stencil payload was not correctly
setup to bytes (U8) to match design but instead was set to word (U16)
causing us to write garbage to the final payload in some cases.

Author: ichenkai

visa/VisaToG4/TranslateSend3D.cpp

@@ -1266,9 +1266,11 @@ IR_Builder::constructSrcPayloadDualRenderTarget(vISA_RT_CONTROLS cntrls,
   auto payloadUD = createSendPayloadDcl(numElts, Type_UD);
   auto payloadUW = createSendPayloadDcl(numElts, Type_UW);
   auto payloadF = createSendPayloadDcl(numElts, Type_F);
+  auto payloadUB = createSendPayloadDcl(numElts, Type_UB);
 
   payloadUW->setAliasDeclare(payloadUD, 0);
   payloadF->setAliasDeclare(payloadUD, 0);
+  payloadUB->setAliasDeclare(payloadUD, 0);
 
   // Check whether coalescing is possible
   // coalesc payload by checking whether the source is already prepared in a
@@ -1398,7 +1400,7 @@ IR_Builder::constructSrcPayloadDualRenderTarget(vISA_RT_CONTROLS cntrls,
     }
 
     if (cntrls.isStencil) {
-      Copy_SrcRegRegion_To_Payload(payloadUW, regOff, S, execSize, instOpt);
+      Copy_SrcRegRegion_To_Payload(payloadUB, regOff, S, execSize, instOpt);
     }
 
     srcToUse = createSrcRegRegion(payloadUD, getRegionStride1());