ixgbe: fix multiple kernel-doc errors

The commit dfaf891d ("ixgbe: Refactor the RSS configuration code")
introduced a few kernel-doc errors:

1) The function name is missing;
2) The format is wrong;
3) The short description is redundant.

Fix all the above for the correct execution of the kernel doc.

Signed-off-by: Jean Sacren <sakiwit@gmail.com>
Tested-by: Darin Miller <darin.j.miller@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>