iommu/vt-d: Change PASID support to bit 40 of Extended Capability Register

The existing hardware implementations with PASID support advertised in
bit 28? Forget them. They do not exist. Bit 28 means nothing. When we
have something that works, it'll use bit 40. Do not attempt to infer
anything meaningful from bit 28.

This will be reflected in an updated VT-d spec in the extremely near
future.

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

include/linux/intel-iommu.h

@@ -115,13 +115,14 @@ static inline void dmar_writeq(void __iomem *addr, u64 val)
  * Extended Capability Register
  */
 
+#define ecap_pasid(e)		((e >> 40) & 0x1)
 #define ecap_pss(e)		((e >> 35) & 0x1f)
 #define ecap_eafs(e)		((e >> 34) & 0x1)
 #define ecap_nwfs(e)		((e >> 33) & 0x1)
 #define ecap_srs(e)		((e >> 31) & 0x1)
 #define ecap_ers(e)		((e >> 30) & 0x1)
 #define ecap_prs(e)		((e >> 29) & 0x1)
-#define ecap_pasid(e)		((e >> 28) & 0x1)
+/* PASID support used to be on bit 28 */
 #define ecap_dis(e)		((e >> 27) & 0x1)
 #define ecap_nest(e)		((e >> 26) & 0x1)
 #define ecap_mts(e)		((e >> 25) & 0x1)