NTB: Clear property bits in BAR value

The lower bits read from a BAR register will contain property bits
that we do not care about. Clear those so that we can use the BAR
values for limit and xlat registers.

Reported-by: Conrad Meyer <cem@freebsd.org>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Jon Mason <jdmason@kudzu.us>
diff --git a/drivers/ntb/hw/intel/ntb_hw_intel.h b/drivers/ntb/hw/intel/ntb_hw_intel.h
index 2eb4add..4d60433 100644
--- a/drivers/ntb/hw/intel/ntb_hw_intel.h
+++ b/drivers/ntb/hw/intel/ntb_hw_intel.h
@@ -245,6 +245,9 @@
 #define NTB_UNSAFE_DB			BIT_ULL(0)
 #define NTB_UNSAFE_SPAD			BIT_ULL(1)
 
+#define NTB_BAR_MASK_64			~(0xfull)
+#define NTB_BAR_MASK_32			~(0xfu)
+
 struct intel_ntb_dev;
 
 struct intel_ntb_reg {