NTB: debugfs device entry

Create a debugfs entry for the NTB device to log the basic device info,
as well as display the error count on a number of registers.

Signed-off-by: Jon Mason <jon.mason@intel.com>
diff --git a/drivers/ntb/ntb_regs.h b/drivers/ntb/ntb_regs.h
index 9774506..0787205 100644
--- a/drivers/ntb/ntb_regs.h
+++ b/drivers/ntb/ntb_regs.h
@@ -62,10 +62,13 @@
 
 #define SNB_DB_HW_LINK		0x8000
 
+#define SNB_UNCERRSTS_OFFSET	0x014C
+#define SNB_CORERRSTS_OFFSET	0x0158
+#define SNB_LINK_STATUS_OFFSET	0x01A2
 #define SNB_PCICMD_OFFSET	0x0504
 #define SNB_DEVCTRL_OFFSET	0x0598
+#define SNB_DEVSTS_OFFSET	0x059A
 #define SNB_SLINK_STATUS_OFFSET	0x05A2
-#define SNB_LINK_STATUS_OFFSET	0x01A2
 
 #define SNB_PBAR2LMT_OFFSET	0x0000
 #define SNB_PBAR4LMT_OFFSET	0x0008
@@ -84,7 +87,7 @@
 #define SNB_PDBMSK_OFFSET	0x0062
 #define SNB_SDOORBELL_OFFSET	0x0064
 #define SNB_SDBMSK_OFFSET	0x0066
-#define SNB_USMEMMISS		0x0070
+#define SNB_USMEMMISS_OFFSET	0x0070
 #define SNB_SPAD_OFFSET		0x0080
 #define SNB_SPADSEMA4_OFFSET	0x00c0
 #define SNB_WCCNTRL_OFFSET	0x00e0