RDMA/hw: i40iw_hmc: Fix misspellings of '*idx' args

RDMA/hw: i40iw_hmc: Fix misspellings of '*idx' args

Fixes the following W=1 kernel build warning(s):

 drivers/infiniband/hw/i40iw/i40iw_hmc.c:64: warning: Function parameter or member 'idx' not described in 'i40iw_find_sd_index_limit'
 drivers/infiniband/hw/i40iw/i40iw_hmc.c:64: warning: Excess function parameter 'index' description in 'i40iw_find_sd_index_limit'
 drivers/infiniband/hw/i40iw/i40iw_hmc.c:94: warning: Function parameter or member 'pd_idx' not described in 'i40iw_find_pd_index_limit'
 drivers/infiniband/hw/i40iw/i40iw_hmc.c:94: warning: Excess function parameter 'pd_index' description in 'i40iw_find_pd_index_limit'

Link: https://lore.kernel.org/r/20210118223929.512175-2-lee.jones@linaro.org
Cc: Faisal Latif <faisal.latif@intel.com>
Cc: Shiraz Saleem <shiraz.saleem@intel.com>
Cc: Doug Ledford <dledford@redhat.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: linux-rdma@vger.kernel.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>