IB/iser: Fix typo in comment

Spelling mistake (triple letters) in comment.
Detected with the help of Coccinelle.

Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Julia Lawall <[e-mail]>
Reviewed-by: Sagi Grimberg <[e-mail]>
Acked-by: Max Gurtovoy <[e-mail]>
Signed-off-by: Jason Gunthorpe <[e-mail]>

drivers/infiniband/ulp/iser/iscsi_iser.h

···
  * @cq:                  Connection completion queue
  * @cq_size:             The number of max outstanding completions
  * @device:              reference to iser device
- * @fr_pool:             connection fast registration poool
+ * @fr_pool:             connection fast registration pool
  * @pi_support:          Indicate device T10-PI support
  * @reg_cqe:             completion handler
  */