comdlg32: Remove inappropriate const qualifier.

dlls/comdlg32/filedlg31.c

diff --git a/dlls/comdlg32/filedlg31.c b/dlls/comdlg32/filedlg31.c
index 9586773..b49cc7e 100644
--- a/dlls/comdlg32/filedlg31.c
+++ b/dlls/comdlg32/filedlg31.c
@@ -754,7 +754,7 @@
  *                              FD31_FreeOfnW          [internal]
  *      Undo all allocations done by FD31_MapOfnStructA
  */
-void FD31_FreeOfnW(const OPENFILENAMEW *ofnW)
+void FD31_FreeOfnW(OPENFILENAMEW *ofnW)
 {
    HeapFree(GetProcessHeap(), 0, (LPWSTR) ofnW->lpstrFilter);
    HeapFree(GetProcessHeap(), 0, ofnW->lpstrCustomFilter);

dlls/comdlg32/filedlg31.h

diff --git a/dlls/comdlg32/filedlg31.h b/dlls/comdlg32/filedlg31.h
index b86bc0f..7328f07 100644
--- a/dlls/comdlg32/filedlg31.h
+++ b/dlls/comdlg32/filedlg31.h
@@ -55,7 +55,7 @@
                                     PFD31_CALLBACKS callbacks, DWORD data);
 extern void FD31_DestroyPrivate(PFD31_DATA lfs);
 extern void FD31_MapOfnStructA(const OPENFILENAMEA *ofnA, LPOPENFILENAMEW ofnW, BOOL open);
-extern void FD31_FreeOfnW(const OPENFILENAMEW *ofnW);
+extern void FD31_FreeOfnW(OPENFILENAMEW *ofnW);
 extern BOOL FD31_CallWindowProc(const FD31_DATA *lfs, UINT wMsg, WPARAM wParam,
                                 LPARAM lParam);
 extern LONG FD31_WMInitDialog(HWND hWnd, WPARAM wParam, LPARAM lParam);