MFC r339626:

cxgbe(4): Use automatic cidx updates with ofld and ctrl queues.

The bits that explicitly request cidx updates do not work reliably with
all possible WRs that can be sent over the queue. The F_FW_WR_EQUIQ
requests that still remain may also have to be replaced with explicit
credit flush WRs in the future.

Approved by: re@ (rgrimes@)
Sponsored by: Chelsio Communications