MFV 29f27e847: "IB/cma: Use cached gids"

This addresses a regression from an earlier upstream change which caused
cma_acquire_dev() to bypass the port GID cache and instead query the HCA
for each entry in its GID table. These queries can become extremely slow on
multiport devices, which has a negative impact on connection setup times.

Discussed with: hselasky
Obtained from: Linux
MFC after: 2 weeks
Sponsored by: EMC / Isilon Storage Division