fm10k: fix a minor typo in some comments

s/funciton/function to resolve a typo, and cleanup grammar on a few
comments regarding processing the VF mailboxes.

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Krishneil Singh <Krishneil.k.singh@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>