devlink: Add new "event_eq_size" generic device param
Add new device generic parameter to determine the size of the
asynchronous control events EQ.
For example, to reduce event EQ size to 64, execute:
$ devlink dev param set pci/0000:06:00.0 \
name event_eq_size value 64 cmode driverinit
$ devlink dev reload pci/0000:06:00.0