Revert "Revert "Staging: rtl8812ae: remove modules field of rate_control_ops""

This reverts commit 161d7855.

Reversal of fortune -- I thought this was going to be resolved by other
means, but that hasn't materialized.  Plus, apparently we now care more
than I realized about not breaking staging drivers...

Signed-off-by: John W. Linville <linville@tuxdriver.com>