cxgbe: set iq flags only after it has been initialized

[gallatin]

Summary

Recent changes caused iq flags, like LRO, to be set before init_iq(). However, init_iq() clears those flags, so they are effectively impossible to set now. This prevented LRO from working for us.

[np]

Thanks for the fix. Please add a "Fixes: 43bbae19483fbde0a91e61acad8a6e71e334c8b8" line to the commit log before checking it in.