MFC r343569, r345307

r343569:
cxgbe/iw_cxgbe: Fix an address calculation in the memory registration code that
was added in r342266.

Submitted by: Krishnamraju Eraparaju @ Chelsio
Sponsored by: Chelsio Communications

r345307:
iw_cxgbe: Remove unused smac_idx from the ep structure.

Submitted by: Krishnamraju Eraparaju @ Chelsio