NTB: correct ntb_peer_spad_addr and ntb_peer_spad_read comment typos

The comment for ntb_peer_spad_addr and ntb_peer_spad_read
incorrectly referred to peer doorbell register and local
scratchpad register.
Signed-off-by: Wesley Sheng <wesley.sheng@amd.com>
Signed-off-by: Jon Mason <jdmason@kudzu.us>

include/linux/ntb.h

@@ -1351,7 +1351,7 @@ static inline int ntb_spad_write(struct ntb_dev *ntb, int sidx, u32 val)
  * @sidx:	Scratchpad index.
  * @spad_addr:	OUT - The address of the peer scratchpad register.
  *
- * Return the address of the peer doorbell register.  This may be used, for
+ * Return the address of the peer scratchpad register.  This may be used, for
  * example, by drivers that offload memory copy operations to a dma engine.
  *
  * Return: Zero on success, otherwise an error number.
@@ -1373,7 +1373,7 @@ static inline int ntb_peer_spad_addr(struct ntb_dev *ntb, int pidx, int sidx,
  *
  * Read the peer scratchpad register, and return the value.
  *
- * Return: The value of the local scratchpad register.
+ * Return: The value of the peer scratchpad register.
  */
 static inline u32 ntb_peer_spad_read(struct ntb_dev *ntb, int pidx, int sidx)
 {