[AsmPrinter] Remove an unnecessary cast (NFC) (#150839)

getLabelAfterInsn() already returns MCSymbol *.

Author: kazutakahirata

llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp

@@ -972,10 +972,9 @@ void DwarfDebug::constructCallSiteEntryDIEs(const DISubprogram &SP,
       // the call graph which could lead to some target function. For tail
       // calls, no return PC information is needed, unless tuning for GDB in
       // DWARF4 mode in which case we fake a return PC for compatibility.
-      const MCSymbol *PCAddr =
-          (!IsTail || CU.useGNUAnalogForDwarf5Feature())
-              ? const_cast<MCSymbol *>(getLabelAfterInsn(TopLevelCallMI))
-              : nullptr;
+      const MCSymbol *PCAddr = (!IsTail || CU.useGNUAnalogForDwarf5Feature())
+                                   ? getLabelAfterInsn(TopLevelCallMI)
+                                   : nullptr;
 
       // For tail calls, it's necessary to record the address of the branch
       // instruction so that the debugger can show where the tail call occurred.