iommu/vt-d: Remove unused PASID_DISABLED

The macro is unused after commit 00ecd540 so it can be removed.
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Fixes: 00ecd540 ("iommu/vt-d: Clean up unused PASID updating functions")
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Link: https://lore.kernel.org/r/20211123105507.7654-2-joro@8bytes.org

arch/x86/include/asm/fpu/api.h

@@ -102,12 +102,6 @@ extern void switch_fpu_return(void);
  */
 extern int cpu_has_xfeatures(u64 xfeatures_mask, const char **feature_name);
 
-/*
- * Tasks that are not using SVA have mm->pasid set to zero to note that they
- * will not have the valid bit set in MSR_IA32_PASID while they are running.
- */
-#define PASID_DISABLED	0
-
 /* Trap handling */
 extern int  fpu__exception_code(struct fpu *fpu, int trap_nr);
 extern void fpu_sync_fpstate(struct fpu *fpu);