cxgbe(4): Use firmware commands to get/set filter configuration.

1. Query the firmware for filter mode, mask, and related ingress config instead of trying to figure them out from hardware registers. Read configuration from the registers only when the firmware does not support this query.

2. Use the firmware to set the filter mode. This is the correct way to do it and is more flexible as well. The filter mode (and associated ingress config) can now be changed any time it is safe to do so.
   
   The user can specify a subset of a valid mode and the driver will enable enough bits to make sure that the mode is maxed out -- that is, it is not possible to set another bit without exceeding the total width for optional filter fields. This is a hardware requirement that was not enforced by the driver previously.

Sponsored by: Chelsio Communications

(cherry picked from commit 7ac8040a99319456c3225cd5166390f5bd172fdf)