[Autobackout][FunctionalRegression]Revert of change: ae382b7: Fix pixel shader input sinking in CodeSinking

CodeSinking moves input intrinsics before their first uses in the
    target basic block. Phi instructions should not be treated as
    valid uses in the currect block as their use is actually in
    a predecessor block.

Author: sys-igc

IGC/Compiler/CISACodeGen/CodeSinking.cpp

@@ -138,7 +138,6 @@ static BasicBlock *findLowestSinkTarget(Instruction *inst, SmallPtrSetImpl<Instr
         break;
     }
   }
-
   BasicBlock *curBlk = inst->getParent();
   Loop *curLoop = LI->getLoopFor(inst->getParent());
   while (tgtBlk && tgtBlk != curBlk) {
@@ -152,7 +151,7 @@ static BasicBlock *findLowestSinkTarget(Instruction *inst, SmallPtrSetImpl<Instr
         // Determine the block of the use.
         Instruction *useInst = cast<Instruction>(*I);
         BasicBlock *useBlock = useInst->getParent();
-        if (useBlock == tgtBlk && !isa<PHINode>(useInst)) {
+        if (useBlock == tgtBlk) {
           usesInBlk.insert(useInst);
         }
       }