NTB: Correct Number of Scratch Pad Registers

The NTB Xeon hardware has 16 scratch pad registers and 16 back-to-back
scratch pad registers.  Correct the #define to represent this and update
the variable names to reflect their usage.
Signed-off-by: NJon Mason <jon.mason@intel.com>

drivers/ntb/ntb_hw.c

@@ -547,7 +547,7 @@ static int ntb_xeon_setup(struct ntb_device *ndev)
 	if (ndev->conn_type == NTB_CONN_B2B) {
 		ndev->reg_ofs.sdb = ndev->reg_base + SNB_B2B_DOORBELL_OFFSET;
 		ndev->reg_ofs.spad_write = ndev->reg_base + SNB_B2B_SPAD_OFFSET;
-		ndev->limits.max_spads = SNB_MAX_SPADS;
+		ndev->limits.max_spads = SNB_MAX_B2B_SPADS;
 	} else {
 		ndev->reg_ofs.sdb = ndev->reg_base + SNB_SDOORBELL_OFFSET;
 		ndev->reg_ofs.spad_write = ndev->reg_base + SNB_SPAD_OFFSET;

drivers/ntb/ntb_regs.h

@@ -53,8 +53,8 @@
 #define NTB_LINK_WIDTH_MASK	0x03f0
 
 #define SNB_MSIX_CNT		4
-#define SNB_MAX_SPADS		16
-#define SNB_MAX_COMPAT_SPADS	8
+#define SNB_MAX_B2B_SPADS	16
+#define SNB_MAX_COMPAT_SPADS	16
 /* Reserve the uppermost bit for link interrupt */
 #define SNB_MAX_DB_BITS		15
 #define SNB_DB_BITS_PER_VEC	5