x86/mm/tlb: Define LOADED_MM_SWITCHING with pointer-sized number

sparse complains that LOADED_MM_SWITCHING's definition casts an int to a
pointer:

  arch/x86/mm/tlb.c:409:17: warning: non size-preserving integer to pointer cast

Use a pointer-sized integer constant instead.

Signed-off-by: Jann Horn <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
Reviewed-by: Mukesh Ojha <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Sai Praneeth <[email protected]>
Cc: Sebastian Andrzej Siewior <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: x86-ml <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

arch/x86/include/asm/tlbflush.h

@@ -167,7 +167,7 @@ struct tlb_state {
 	 */
 	struct mm_struct *loaded_mm;
 
-#define LOADED_MM_SWITCHING ((struct mm_struct *)1)
+#define LOADED_MM_SWITCHING ((struct mm_struct *)1UL)
 
 	/* Last user mm for optimizing IBPB */
 	union {