fix amdgpu.permlane_swap code example

Author: tgymnich

mlir/include/mlir/Dialect/AMDGPU/IR/AMDGPU.td

@@ -670,8 +670,8 @@ def AMDGPU_PermlaneSwapOp : AMDGPU_Op<"permlane_swap", [Pure, AllTypesMatch<["re
 
     Example:
     ```mlir
-    %0 = amdgpu.permlane %src 16 : f16
-    %1 = amdgpu.permlane %src 32 { fetch_inactive = true, bound_ctrl = true } : f16
+    %0 = amdgpu.permlane_swap %src 16 : f16
+    %1 = amdgpu.permlane_swap %src 32 { fetch_inactive = true, bound_ctrl = true } : f16
     ```
 
     Operands:

mlir/lib/Conversion/AMDGPUToROCDL/AMDGPUToROCDL.cpp

@@ -1893,7 +1893,7 @@ struct AMDGPUPermlaneLowering : public ConvertOpToLLVMPattern<PermlaneSwapOp> {
     Location loc = op.getLoc();
     Type i32 = rewriter.getI32Type();
     Value src = adaptor.getSrc();
-    unsigned row_length = op.getRowLength();
+    unsigned rowLength = op.getRowLength();
     bool fi = op.getFetchInactive();
     bool boundctrl = op.getBoundCtrl();
 
@@ -1906,10 +1906,10 @@ struct AMDGPUPermlaneLowering : public ConvertOpToLLVMPattern<PermlaneSwapOp> {
       Type i32pair = LLVM::LLVMStructType::getLiteral(
           rewriter.getContext(), {v.getType(), v.getType()});
 
-      if (row_length == 16)
+      if (rowLength == 16)
         res = ROCDL::Permlane16SwapOp::create(rewriter, loc, i32pair, v, v, fi,
                                               boundctrl);
-      else if (row_length == 32)
+      else if (rowLength == 32)
         res = ROCDL::Permlane32SwapOp::create(rewriter, loc, i32pair, v, v, fi,
                                               boundctrl);
       else